Question

A charged particle is moving on circular path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes

• A. 8 times
• B. 4 times
• C. 2 times
• D. 16 times

Answer 1

Answer: (B)

4 times

Answer 2

As $\mathrm { Bqv } = \frac { \mathrm { mv } ^ { 2 } } { \mathrm { r } }$ or

According to the question $\mathrm { v } ^ { \prime } = 2 \mathrm { v }$ and $\mathrm { B } ^ { \prime } = \frac { \mathrm { B } } { 2 }$