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A small object with charge q and weight ...

A small object with charge q and weight mg is attached to one end of a string of length 'L' attached to a stationary support. The system is placed in a uniform horizontal electric field 'E, as shown in the accompanying figure. In the presence of the field, the string makes a constant angle with the vertical. The sign and magnitude of q-

A

Positive with magnitude `(mg)/(E)`

B

Positive with magnitude `((mg)/(E)) tan theta`

C

Negative with magnitud `(mg)/(E) tan theta`

D

Positive with magnitude `E(tan theta)/(mg)`

Text Solution

Verified by Experts

The correct Answer is:
B

`T cos theta=mg`
`T sin theta=qE`
`"tan" theta=(qE)/(mg) :. a=(mg tan theta)/(E)`
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