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Sat October 25, 2014  

Ans: Gravitational force is actually the force of attraction between two bodies due to their masses. The force of attraction between the earth and any other body lying on or near its surface is called gravitational force of earth or gravity. By Newtons second law we know that a body acted upon by an unbalanced force gets accelerated in the direction of force. The acceleration produced on a freely falling body by the gravitataional  pull of the earth is called the acceleration due to gravity and is denoted as 'g' .  The value of g near the surface of earth is taken as 9.8 m/s 2  . Sometimes 10 m/ s 2  is also used in certain cases which is just an appoximation of the value 9.8 m/s 2 . The correct value of g is 9.8 m/s 2  .

Fri October 24, 2014  

Ans: Dear jaiswalr550@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
The scope of this helpdesk is to answer subject related queries which are relevant to understanding concepts and solving problems. Hence we regret that we would not be able to answer your query.

Regards

Topperlearning Team.

Fri October 24, 2014  

Ans: Dear jaiswalr550@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
The scope of this helpdesk is to answer subject related queries which are relevant to understanding concepts and solving problems. Hence we regret that we would not be able to answer your query.

Regards

Topperlearning Team.

Fri October 24, 2014  

Ans: Dear jaiswalr550@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
The scope of this helpdesk is to answer subject related queries which are relevant to understanding concepts and solving problems. Hence we regret that we would not be able to answer your query.

Regards

Topperlearning Team.

Fri October 24, 2014  

1. The focal length of an equiconvex lens in air is equal to either of its radii of curvature. the refractive index of the material of lens is __________
2. A charge of 4x10^-8C is uniformly distributed over the surface of sphere radius 1cm. another hollow sphere of radius 5cm is concentric with the small sphere. find intensity of electric field at a distance 2cm from centre. [K=9x10^9 MKS] [ans in NC^-1]
3. A light of 4560angstrom and 1mW is made incident on photosensitive surface of Cs. If efficiency of surface is 0.1%, then photoelectric current produces is___________
4.A spherical drop of water has 3x10^-10C charge on its surface. 300 volt electric potential exists on its surface. if 27 such identical drops are combined to form a single drop, calculate electric potential on the surface of new drop._____________
Ans: 2.    Given charge Q = 4 × 10 -8 C.  begin mathsize 14px style Let space straight P space be space straight a space point space at space straight a space distance space of space straight r space left parenthesis 2 space cm right parenthesis space away space from space the space centre. To space find space the space field space at space straight P space let space us space consider space straight a space gaussian space surface space through space the space point space straight P space as space shown space in space the space figure. We space can space write space that space the space flux space through space this space surface space equals space contour integral space straight E with rightwards arrow on top. dS with rightwards arrow on top space space space space space space equals space contour integral straight E. space dS space space space space space space equals straight E contour integral dS space space space space space space equals space 4 cross times straight pi cross times straight r squared cross times straight E Here space straight r space equals space 2 space cm space equals space 2 space cross times 10 to the power of minus 2 space end exponent straight m According space t o space Gauss space Law comma space this space flux space is space equal space to space the space charge space straight Q space enclosed space by space the space surface space divided space by space straight epsilon subscript 0. straight i. straight e. space space contour integral space straight E with rightwards arrow on top. dS with rightwards arrow on top space equals space straight Q over straight epsilon subscript 0 4 cross times straight pi cross times straight r squared cross times straight E space equals straight Q over straight epsilon subscript 0 4 cross times straight pi cross times left parenthesis 2 cross times 10 to the power of minus 2 end exponent right parenthesis space squared cross times straight E space equals straight Q over straight epsilon subscript 0 On space rearranging space we space get space : straight E space equals space fraction numerator straight Q over denominator straight epsilon subscript 0 cross times 4 cross times straight pi cross times left parenthesis 2 cross times 10 to the power of minus 2 end exponent right parenthesis squared space end fraction open parentheses we space know space that space fraction numerator 1 over denominator 4 πε subscript 0 end fraction equals k equals 9 cross times 10 to the power of 9 space Nm squared straight C to the power of minus 2 end exponent space space close parentheses space space space space equals 9 cross times 10 to the power of 9 space Nm squared straight C to the power of minus 2 end exponent cross times fraction numerator 4 cross times 10 to the power of minus 8 end exponent space straight C over denominator 4 cross times 10 to the power of minus 4 end exponent space straight m squared end fraction straight E space equals 9 space cross times space 10 to the power of 5 space straight N space straight C to the power of minus 1 end exponent end style The Electric field at a distance 2cm from centre = 9 × 10 5 N C -1   Note: Please ask other questions (each question) as seperate separate queries.

Fri October 24, 2014  

1. The focal length of an equiconvex lens in air is equal to either of its radii of curvature. the refractive index of the material of lens is __________
2. A charge of 4x10^-8C is uniformly distributed over the surface of sphere radius 1cm. another hollow sphere of radius 5cm is concentric with the small sphere. find intensity of electric field at a distance 2cm from centre. [K=9x10^9 MKS] [ans in NC^-1]
3. A light of 4560angstrom and 1mW is made incident on photosensitive surface of Cs. If efficiency of surface is 0.1%, then photoelectric current produces is___________
4.A spherical drop of water has 3x10^-10C charge on its surface. 300 volt electric potential exists on its surface. if 27 such identical drops are combined to form a single drop, calculate electric potential on the surface of new drop._____________
Ans: 1.   Given Focal length, f = R Being an equiconvex lens, let R 1  = R ,  R 2  = - R  begin mathsize 14px style According space to space lens space makers space formula : space 1 over straight f equals open parentheses straight mu minus 1 close parentheses open parentheses 1 over straight R subscript 1 minus 1 over straight R subscript 2 close parentheses Substituting space the space values space we space get : 1 over straight R equals open parentheses straight mu minus 1 close parentheses open parentheses 1 over straight R plus 1 over straight R close parentheses 1 over straight R equals open parentheses straight mu minus 1 close parentheses 2 over straight R 1 half plus 1 equals straight mu rightwards double arrow space straight mu space equals space 3 over 2 equals 1.5 end style  The refractive index of the material of lens is 1.5   Note: Please ask other questions (each question) as seperate separate queries.

Fri October 24, 2014  

Ans: 5 to the power of 2 x minus 1 end exponent minus 25 to the power of x minus 1 end exponent equals 25000 rightwards double arrow 25 to the power of x over 5 minus 25 to the power of x over 25 equals 25000 rightwards double arrow 25 to the power of x open parentheses 1 fifth minus 1 over 25 close parentheses equals 25000 rightwards double arrow 25 to the power of x open parentheses fraction numerator 5 minus 1 over denominator 25 end fraction close parentheses equals 25000 rightwards double arrow 25 to the power of x cross times 4 over 25 equals 25000 rightwards double arrow 25 to the power of x equals 25000 cross times 25 over 4 rightwards double arrow 25 to the power of x equals 25 cross times 1000 over 4 cross times 25 rightwards double arrow 25 to the power of x equals 25 cross times 250 cross times 25 rightwards double arrow 25 to the power of x equals open parentheses 25 close parentheses cubed cross times 10 I f space i n space t h i s space q u e s t i o n comma space t h e space R H S space w o u l d space h a v e space b e e n space 2500 comma space t h e n space t h e space a n s w e r space w o u l d space h a v e space b e e n space rightwards double arrow 25 to the power of x equals 25 cubed rightwards double arrow x equals 3 space left square bracket I f space b a s e s space a r e space s a m e comma space p o w e r s space a r e space e q u a l right square bracket I f space t h e space R H S space i s space n o t space 2500 comma space o r space t h e r e space a r e space a n y space o t h e r space c h a n g e s comma space t h e n space log a r i t h m space h a v e space t o space b e space u s e d. P l e a s e space i n f o r m space a b o u t space t h e space c o r r e c t space q u e s t i o n.

Fri October 24, 2014  

Ans: cos space theta equals 1 half rightwards double arrow cos space theta equals space cos space 60 degree rightwards double arrow theta space equals space 60 degree space left square bracket R e m o v i n g space cos space f r o m space b o t h space s i d e s right square bracket therefore cos space theta plus sin space theta equals cos space 60 degree plus sin space 60 degree equals 1 half plus fraction numerator square root of 3 over denominator 2 end fraction equals fraction numerator 1 plus square root of 3 over denominator 2 end fraction

Fri October 24, 2014  

Ans: because increment A B C almost equal to increment R P Q comma I f space t w o space t r i a n g l e s space a r e space s i m i l a r comma space t h e n space c o r r e s p o n d i n g space s i d e s space a r e space p r o p o r t i o n a l. fraction numerator R P over denominator A B end fraction equals fraction numerator P Q over denominator B C end fraction equals fraction numerator R Q over denominator A C end fraction rightwards double arrow 6 over 3 equals 10 over 5 equals fraction numerator R Q over denominator 6 end fraction therefore 10 over 5 equals fraction numerator R Q over denominator 6 end fraction rightwards double arrow R Q equals fraction numerator 10 cross times 6 over denominator 5 end fraction rightwards double arrow R Q equals 12 space c m therefore Q R equals 12 space c m

Thu October 23, 2014  

Ans: With regard to this chapter, mobilisation is a way in which public opinion is formed,  mobilised and driven. For example, if we want to drive a cleaning campaign in the country, then we first have to create a public opinion and make people aware of the situation. This can be done by advertisement campaigns, holding street plays, organising sabhas etc. In this way, public opinion can be mobilised . An organisation is is an institution that is formed or set up on the basis of cetain principles and guidelines with definite aims and objectives. 

Wed October 22, 2014  

Ans: T h e space a m o u n t space o f space a i r space p r e s e n t space i n space a space c y l i n d e r space w h e n space a space v a c u u m space p u m p space r e m o v e s space 1 fourth space o f space t h e space a i r space r e m a i n i n g space i n space t h e space c y l i n d e r space a t space a space t i m e. S o l u t i o n : space L e t space t h e space a m o u n t space o f space a i r space b e space x space c m cubed A m o u n t space o f space a i r space l e f t space a f t e r space r e m o v i n g space 1 fourth o f space a i r space i n space c y l i n d e r space equals x minus space x over 4 equals fraction numerator 3 x over denominator 4 end fraction space c m cubed A m o u n t space o f space a i r space l e f t space a f t e r space s e c o n d space r e m o m v a l equals fraction numerator 3 x over denominator 4 end fraction minus 1 fourth open parentheses fraction numerator 3 x over denominator 4 end fraction close parentheses equals fraction numerator 12 x minus 3 x over denominator 16 end fraction equals fraction numerator 9 x over denominator 16 end fraction c m cubed A m o u n t space o f space a i r space a f t e r space t h i r d space r e m o v a l equals fraction numerator 9 x over denominator 16 end fraction minus 1 fourth open parentheses fraction numerator 9 x over denominator 16 end fraction close parentheses equals fraction numerator 27 x over denominator 64 end fraction c m cubed L e t space t subscript 1 equals fraction numerator 3 x over denominator 4 end fraction comma space t subscript 2 equals fraction numerator 9 x over denominator 16 end fraction comma space t subscript 3 equals fraction numerator 27 x over denominator 64 end fraction because t subscript 2 minus t subscript 1 not equal to t subscript 3 minus t subscript 2 therefore T h e space s e r i e s space i s space n o t space i n space A P A P space i s space A i r t h m e t i c space P r o g r e s s i o n comma space G P space i s space G e o m e t r r i c space P r o g r e s s i o n. I f space i n space a space s e r i e s comma space t h e space d i f f e r e n c e space b e t w e e n space t w o space c o n s e c u t i v e space t e r m s space i s space s a m e space t h r o u g h o u t space t h e space s e r i e s comma space t h e n space t h e space s e r i e s space i s space a n A P. I f space i n space a space s e r i e s comma space t h e space r a t i o space o f space t w o space c o n s e c u t i v e space t e r m s space i s space s a m e space t h r o u g h o u t space t h e space s e r i e s. space t h e n space t h e space s e r i e s space i s space a space G P F o r space e x a m p l e comma space 1 comma 3 comma 5 comma 7 comma.... space i s space a n space A P. 2 comma 4 comma 8 comma 16 comma..... i s space a space G P

Wed October 22, 2014  

Ans: Dear bhavanabhat84@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.
We have not understood the query that you have posted. We would request you to clarify / provide additional details so that we may answer this to the best of the ability. Please repost the question with the proper diagram.

Regards

Topperlearning Team.

Tue October 21, 2014  

Ans: A pressure group is a group of people who come together on a platform to influence the policies of the government. They share political, social and economic interests and aim at achieving the same political goal. Pressure groups play a very important role in a democracy. A democratic government has to look after the aspirations of the people belonging to each and every section of the society. Thus if a pressure group represent the interest of one particular community in an unjustified way, then it may pose danger to the democracy. For example, if a small community of businessmen and industrialists exert pressure on the government to pass a certain law which may harm the interests of workers and consumer, then the democratic structure of the country may suffer, However, it is also to be noticed that it is not possible for a small section of people to exert influence on the government every time. In a second scenario, if a pressure group represents the interests of a neglected section of society and organizes a movement to restore their rights and powers, it strengthens the forces of democracy. Therefore, we can say that the above statement may be correct and incorrect depending upon the interests of the group that is represented by the pressure groups. 

Tue October 21, 2014  

Ans: The Bolivian war was fought over the control of water resources. Many people belonging to different professional, academic, social and economic backgrounds came out together to protest against the water woes of the country. This war reflects that pressure groups can influence the decisions of the government by directly participating in politics. This can be done by mobilizing people, generating public opinion and contesting public elections. But not every pressure group can contest elections. Under this scenario, activities may be undertaken by the interest or the pressure group to promote their views or the opinions. This war also tells us that no organization can take away the right of people on using essential commodities. If this happens, then people may organise themselves and can lead a movement from the front.  

Tue October 21, 2014  

Ans: Followers of any popular movement should have the values of honesty, determination, strong will power, unity and faith in democracy to make their movement successful.

Tue October 21, 2014  

Ans: left parenthesis i right parenthesis space fraction numerator 3 cross times 27 to the power of n plus 1 end exponent plus 9 cross times 3 to the power of 3 n minus 1 end exponent over denominator 8 cross times 3 to the power of 3 n minus 5 end exponent plus 27 to the power of n end fraction equals fraction numerator 3 cross times 27 to the power of n cross times 27 plus 9 cross times begin display style 27 to the power of n over 3 end style over denominator 8 cross times begin display style 27 to the power of n over 243 end style plus 27 to the power of n end fraction equals fraction numerator 3 cross times 27 plus begin display style 3 end style over denominator begin display style 8 over 243 end style plus 1 end fraction equals fraction numerator 84 cross times 243 over denominator 251 end fraction  left parenthesis i i right parenthesis space P l e a s e space r e p o s t space t h e space s e c o n d space q u e s t i o n space c o r r e c t l y.

Tue October 21, 2014  

Ans: SPA was an alliance of seven parties that came together to protest against the discontinuation of democratic rule in Nepal by a monarch. SPA wanted to establish a democratic rule in Nepal. The members of SPA were mainly political workers across Nepal. FEDECOR was an organization formed in Bolivia which wanted the government to end the privatization of water resources in the country. This organization consisted of the environmentalists, academicians, engineers etc. unlike SPA which was an alliance of the political parties in Nepal. However, FEDECOR had the backing and support of the Socialist Party of Bolivia. 

Tue October 21, 2014  

Ans: L e t space t h e space s h a r e space o f space R i t a space b e space x. therefore S h a r e space o f space S e e m a space equals 500 minus x 1 third space s h a r e space o f space R i t a equals 1 half s h a r e space o f space S e e m a rightwards double arrow 1 third x equals 1 half left parenthesis 500 minus x right parenthesis rightwards double arrow x over 3 equals 250 minus x over 2 rightwards double arrow x over 3 plus x over 2 equals 250 rightwards double arrow fraction numerator 5 x over denominator 6 end fraction equals 250 rightwards double arrow x equals fraction numerator 250 cross times 6 over denominator 5 end fraction therefore x equals 300 S h a r e space o f space R i t a space equals R s. space 300 S h a r e space o f space S e e m a space equals R s. space 200

Mon October 20, 2014  

Ans: Angular momentum of a body about a given axis is the product of linear momentum and the perpendicular distance of line of action of linear momentum vector from the axis of rotataion. This is the physical meaning of angular momentum .  i.e Syntax error from line 1 column 49 to line 1 column 73. Unexpected '<mstyle '. Angular momentum is a vector quantity.  Geometrical meaning of angular momentum . 
 

   

Mon October 20, 2014  

Ans: 2 square root of 2 x plus 1 end root minus 2 x equals 1 rightwards double arrow 2 square root of 2 x plus 1 end root equals 1 plus 2 x rightwards double arrow 4 left parenthesis 2 x plus 1 right parenthesis equals left parenthesis 1 plus 2 x right parenthesis squared space left square bracket S q u a r i n g space b o t h space s i d e s right square bracket rightwards double arrow 8 x plus 4 equals 4 x squared plus 4 x plus 1 rightwards double arrow 4 x squared minus 4 x minus 3 equals 0 rightwards double arrow 4 x squared minus 6 x plus 2 x minus 3 equals 0 rightwards double arrow 2 x left parenthesis 2 x minus 3 right parenthesis plus 1 left parenthesis 2 x minus 3 right parenthesis equals 0 rightwards double arrow left parenthesis 2 x minus 3 right parenthesis left parenthesis 2 x plus 1 right parenthesis equals 0 x equals 3 over 2 comma minus 1 half
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