Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

A beam of electrons, moving with avelocity of 10^7m/s, enters midway between two horizontal parallel plates in a directions parallel to the plates. Each plate is 5 cm long. These plates are kept 2 cm apart and a potential difference of 90 V is applied between, them. Calculate the velocity of the electron- beam with which it just grazes the edge of the positive plate. (e  /m=1.8×10^{11}  c/kg)
Asked by arjunsah797 | 18 Mar, 2022, 12:06: PM
answered-by-expert Expert Answer
when electron beam enters the region between parallel plates , it is subjected to electric field due to electrical
potential difference applied between parallel plates .

Hence it is accelerated in vertical direction and gains velocity in vertical direction.
 
Magnitude of Force acting on electron , F = e E = e ( V/d)
 
where e is the charge on electron,  E is electric field intensity, V is potential difference and d is distance between plates
 
acceleration = force / mass = (e/m) ( V/d ) = 1.8 × 1011 × ( 90 / 0.02 ) = 8.1 × 1014 m/s2
 
Time t for electron to travel the distance that equals the length of plate = distance / velocity
 
t = 0.05 / 107 = 5 × 10-9 s
 
velocity vy gained in vertical direction when electron beam grazes the edge of positive plate is
determined from the following equation
 
vy = a × t = 8.1 × 1014 × 5 × 10-9 = 0.405 × 107 m/s
 
magnitude of velocity of electron when electron beam grazes the edge of positive plate is given as
 
begin mathsize 14px style v space equals space square root of v subscript x superscript 2 plus v subscript y superscript 2 end root space equals 10 to the power of 7 space square root of 1 plus left parenthesis 0.405 right parenthesis squared end root space m divided by s space equals space 1.079 space cross times 10 to the power of 7 space end exponent m divided by s end style
Answered by Thiyagarajan K | 18 Mar, 2022, 02:08: PM

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 12-science - Physics
I don't know which concept and formula is used
question image
Asked by adityagalar2007 | 06 Apr, 2024, 01:06: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
what is the mass of the bidy
question image
Asked by amlanmcob | 06 Apr, 2024, 12:27: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
a charge of 2microcoulomb experience a force of 6N when placed at a point in an electric field .find electric field at that point
Asked by manishamunda787 | 02 Apr, 2024, 11:07: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
d derive an expression for electric field intensity due to uniformly charged ring on it axix
question image
Asked by kalsichaitanya | 30 Dec, 2023, 04:08: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
1st
question image
Asked by evachauhan15 | 29 Dec, 2023, 10:25: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
what is electric field intensity? What is its S.I unit?
Asked by glorialyanzaw | 13 Oct, 2023, 05:53: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
answer
question image
Asked by r01raunak | 23 May, 2023, 10:24: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
an infinite line charge produces a field of 9×10^4 N/C at a distance of 2 cm calculate the linear charge
Asked by srishtijha944 | 15 Jul, 2022, 09:55: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Three charges \( 1 \mathrm{C},-1 \mathrm{C} \), and \( 2 \mathrm{C} \) are kept on \( X \) axis \( -5 \mathrm{~cm}, x=0 \mathrm{~cm} \) amd \( x=10 \mathrm{~cm} \) respectively find net force one each of them
Asked by marshelojigas | 28 Jun, 2022, 06:46: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
ln a Millikan’s oil drop experiment, the horizontal plates are 1.5 cm apart. With the electric field switch off an oil drop is observed to fall with a steady velocity of 2.5×10^{-2}  cm  s^{-1}.  When the field is switched on the upper plate being positive, the drop just remains stationary when the   p.d.   between the plates is 1500 V. Calculate the radius of drop (b) How many electronic charges does it carry? (c)If the   p.d. between the two plates remains unchanged, with what velocity will the drop move when it has collected two more as a result of exposure to ionising radiation? (Oil density, rho=900 kgm^{3} , Viscosity of air,   eta =1.8×10^{-5} Nsm^{-2}, Density of air,  σ=1.293  kg  m^{-3})
Asked by arjunsah797 | 01 Apr, 2022, 07:31: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Get Latest Study Material for Academic year 24-25 Click here
×