1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# A disc of radius R is uniformly charged with total charge Q. Find the direction and magnitude of the electric field at the point P lying a distance x from the centre of the disc along the axis of symmetry of the disc. Given- k=14πϵ0σ=QπR2

A
2πkσ[1x(x2+R2)3/2]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
σ2ϵ0[1x(x2+R2)3/2]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
Q2πϵ0R2[1x(x2+R2)3/2]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
All of the above
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

## The correct option is D All of the aboveLet the disk be broken into the rings of radius R, and thickness dr.Total charge of a ring is σ2πσ.dr⟹λ2πr∴λ is the line charge of each ring.ERing=14πEc(σdr)2πrx(r2+x2)3/2→Edisk=14πϵ02πσx∫0Rr(r2+x2)3/2dr⟹14πϵ02πσx[1x−1√R2+x2]^x⟹2πσ4πϵ0[1−x√R2+x2]^x⟹2πkσ⎡⎢ ⎢ ⎢⎣1−x(x2+R2)3/2⎤⎥ ⎥ ⎥⎦or, σ2ϵ0⎡⎢ ⎢ ⎢⎣1−x(x2+R2)3/2⎤⎥ ⎥ ⎥⎦, or, Q2πϵ0R2⎡⎢ ⎢ ⎢⎣1−x(x2+R2)3/2⎤⎥ ⎥ ⎥⎦

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Electric Field Due to Charge Distributions - Approach
PHYSICS
Watch in App
Join BYJU'S Learning Program