IIT JEE , AIEEE Forum - Physics , Electricity

ankit3232

two identical small balls, each of mass m amd having charge q are suspended by two light inelastic conducting threads each of length l from the same fixed pont support. if the distanced between the two balls is vey less, then d is equal to?

raulrag009

what is d
do u want the angle

Just balance the forces on a ball

krishna.gopal

If d is distance between them then, assume angle between strings is theta
theta= d/l
Tcos(theta/2)=mg
Tsin(theta/2)= kq^2/d^2
For small angle cos(theta/2)=1
sin(theta/2)=d/2l
So mgd/2l=kq^2/d^2
So
d=(2kq^2l/mg)^(1/3)

a.z

f=mg tan (theta) , when theta is small tan theta $\approx$ sin theta

f=1\4pie $\text{\euro}$ o (q²\d²)

1\4pie $\text{\euro}$ o (q²\d²)=mg sin theta sin theta =d\2L

simplifying, Lq²\2pie $\text{\euro}$ omg = d³

d=(Lq²\2pie $\text{\euro}$ omg)^1\3..

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