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CBSE Class 10 Answered

Prove mathematically that r=2f for mirror.  
Asked by shyamala.holla3 | 16 Feb, 2018, 03:35: PM
answered-by-expert Expert Answer
Let us refer the above figure to prove focal distance is half of radius of curvature.
 
Let us consider a parallel ray RQ passing through focal point F after reflection. Let us join QC. 
begin mathsize 12px style angle R Q C space equals space angle Q C F space equals space theta space b e c a u s e space R Q space i s space p a r a l l e l space t o space C F angle R Q C space equals space angle C Q F space equals space theta space left parenthesis l a w space o f space r e f l e c t i o n right parenthesis h e n c e space angle Q C F space equals space space angle C Q F space equals space theta space a n d space triangle Q C F space i s space i s o c e l e s s h e n c e space C F space equals space F Q f o r space m i r r o r space o f space l a r g e space r a d i u s space o f space c u r v a t u r e comma space F Q space almost equal to space F P space h e n c e space C F space equals space F P space a n d space F P space equals space 2 cross times C P i. e space r space equals space 2 f end style
Answered by Thiyagarajan K | 16 Feb, 2018, 05:40: PM
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CBSE 10 - Science
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what is the role of acid in our stomach
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Maharashtra State Board Exam Class 10 Physics (2024) The SI unit of heating is _____________ (A) Calorie   (B) Joule (C) Kcal/kg  ºC (D) Cal/g ºC
Asked by sagarmishra | 18 Mar, 2024, 04:10: PM
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CBSE 10 - Science
when hydrogen gas burns in presence of oxygen then water is formed and when water is electrolysed then hydrogen and oxygen gases are produced . state which type of reaction takes place
Asked by srinivasansriharinia9 | 01 Mar, 2024, 08:17: PM
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CBSE 10 - Science
Red brown gas is release along with oxygen and lead oxide on heating lead nitrate it is example of which reaction
Asked by muskanprayagraj78 | 26 Feb, 2024, 05:44: PM
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CBSE 10 - Science
An electric refrigerator rated 1 kW operates 6 hours daily. What is the cost of the energy to operate it for 15 days at rate of ₹ 3.00 per kWh?
Asked by kmannatpreet4 | 21 Feb, 2024, 07:34: PM
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CBSE 10 - Science
four wires of each 0f the same length diameter and material are connected to form a square,If the resistance of each wire is R.then equivalent resistance accross the opposite corner is
Asked by umaambiger87 | 08 Feb, 2024, 03:28: PM
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CBSE 10 - Science
Soaps and detergents are both types of salts. Stare the difference between the hws. Write the mechanism of the cleansing action of soups. Why de soaps not form lather (foam with hard water? Mention any wo problems that arise due to the war of detergents instrad of soaps
Asked by pvasanth3573 | 07 Feb, 2024, 10:13: PM
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CBSE 10 - Science
difference between saturated and unsaturated hydrocarbon
Asked by samirankarmakar2702 | 07 Feb, 2024, 09:59: PM
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