# 15 - Capacitors Questions Answers

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Submit By: MANISH SIR 6 year ago
is this topic helpfull: 76 21
Physics >> Electricity >> Capacitors Board Exam

What is the main priniciple  strore energy in a capacitor ?

Asked By: DIBYA JYOTI DEKA 3 year ago
Physics >> Electricity >> Capacitors Engineering Exam

A capacitor of capacity 0.1 μF connected in series to a resistor of 10 MΩ is charged to a certain potential and then made to discharge through resistor. The time in which the potential will take to fall to half its original value is (Give, log102 = 0.3010)

Asked By: SAUMYA PALIWAL 5 year ago

When An external resistance R is connected with the battery of emf E and internal resistane r, what is the maximum power?

Asked By: 5 year agoSolved By: SARIKA
Physics >> Electricity >> Capacitors Medical Exam

distance b/w plate of capacitor C &q charge is increased to double . work done=??

as distance d is double thus C= Ae/2d  thus capacitance will be halved so wd shld be (1/2 )q2/(C/2)   ie 1/4 q2/C

BUT Sir the ans given is=( 1/2)q2/C Plzz do me a little favour by solving this query

Asked By: SARIKA SHARMA 6 year ago

(1/2 )q2/(C/2) = q2/C not 1/4 q2/C

so work done = new energy - previous energy

Physics >> Electricity >> Capacitors Medical Exam

a II plate capacitor has an electric field of 105 V/m b/w d plates . if charge on capacitor plate is 1uC d force on each capacitor is??

ans 0.05N

Asked By: SARIKA SHARMA 7 year ago

F = σq/2ε0 = Eq/2 = 105*10-6/2 = 0.05

A charge of +2.0 x 10^-8 C is placed on the positive plate and a charge of -1.0 x 10^-8 C on the negative plate of a parallel plate capacitor of capacitance 1.2 x 10^-3 uF. Calculate the potential difference developed between the plates. Please add explanation!

Asked By: VISHWAJEET MISHRA 7 year ago

due to induction the charges on the four faces will be

so V = q/C = 1.5 * 10-8/1.2 * 10-9

solve now

One end of a 10cm long silk thread is fixed to a large vertical surface of a charged nonconducting plate having a mass 10g and a charge of 4*10^-6 c . In equlibrium the thread makes an angle of 60 deg. With he vertical.find the surface charge density on plate.
Asked By: GAURAV MAHATE 7 year ago

according to the diagram

tanθ = qE/mg = q(σ/2ε0)/mg

solve this eq. for σ.

Remember that length of the thread is not applicable in the question.

there is slight mistake in last line of previous question.it was find the work done on the system in the process of inserting the slab.
Asked By: GAURAV MAHATE 7 year ago

initial energy of capacitor = 1/2 CV2

final energy of capacitor = 1/2 KC (V/K)2

difference ?

a parallel plate capacitor of plate A and plate seperation d is charged to a potential dif. V and then the battery is disconnected .a slab of dielectric constant K is then inserted between the plates of capacitor so as tofill the space bet. The plates .find the work done in this process.
Asked By: GAURAV MAHATE 7 year ago

initial energy of capacitor = 1/2 CV2

final energy of capacitor = 1/2 KC (V/K)2

difference ?

Calculate potential difference across a and b ,

Asked By: AMIT DAS 7 year ago