1800-150-456-789
FlagBACK
Flag IIT JEE Entrance Exam> Two identical small equally charged condu...
question mark

Two identical small equally charged conducting balls are suspended from long threads secured at one point. The charges and masses of the balls are such that they r in =lbm when the distance b/w them is a (the length of thread L is a). One of the balls is then discharged. What will be the distance b (b

Shikhar srivastava , 7 Years ago
Grade 12th pass
anser 1 Answers
Arun

Last Activity: 4 Years ago

For equilibrium, Tsinθ=F= 
4πϵ 
0
​ 
 a 
2
 
q 
2
 
​ 
 ....(1)
and Tcosθ=mg.....(2)
(1)/(2),tanθ= 
4πϵ 
0
​ 
 a 
2
 mg
q 
2
 
​ 
 
For small θ,tanθ∼ 
L
a/2
​ 
 
∴ 
L
a/2
​ 
 = 
4πϵ 
0
​ 
 a 
2
 mg
q 
2
 
​ 
 
or a 
3
 = 
4πϵ 
0
​ 
 mg
q 
2
 L
​ 
 ....(3)
When one of the balls is discharged, the balls come closer and touch each other and again separate due to repulsion. Due to charge induction,the charge on each ball after touching each other is  
2
q
​ 
 .
Replacing q with q/2 in (3), we get
b 
3
 = 
4πϵ 
0
​ 
 mg
(q/2) 
2
 L
​ 
 ....(4)
(3)/(4), 
b 
3
 
a 
3
 
​ 
 =4

Provide a better Answer & Earn Cool Goodies

Enter text here...
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...

Other Related Questions on IIT JEE Entrance Exam

question mark
My rank is 29k, General, should I opt for any state college cse branch or some Nits in which in which I am getting ECE , chemical, mechanics etc....
IIT JEE Entrance Exam
0 Answer Available

Last Activity: 2 Year ago(s)

question mark
How is Ranquer Eduzone,comparing, Akash,Fitjee,Resonance,Naryana
IIT JEE Entrance Exam
0 Answer Available

Last Activity: 2 Year ago(s)

question mark
Can class 9th students study syllabus classof 11th
IIT JEE Entrance Exam
3 Answer Available

Last Activity: 2 Year ago(s)

question mark
Sum of series 2[n/2] ! [n/2]!/ n! [2Co-2C2+3C2....+[-1]^n[n+1]2Cn] where n is an even positive integer. Kindly provide solution of this question and how to generalise this. How do we know that which expansion will give this?
IIT JEE Entrance Exam
1 Answer Available

Last Activity: 2 Year ago(s)

question mark
I m foreigner,How much mark i need to get into IIT??
IIT JEE Entrance Exam
1 Answer Available

Last Activity: 2 Year ago(s)