Q. 24.8( 5 Votes )
A charged particle is whirled in a horizontal circle on a frictionless table by attaching it to a string fixed at one point. If a magnetic field is switched on in the vertical direction, the tension in the string
A. will increase
B. will decrease
C. will remain the same
D. may increase or decrease
Answer :
Force is depending upon the direction of the whirl and also charge of a particle. Which type of charge particle it is not given. And We don’t know which direction the whirl is rotating. Based on these things we can say that force(tension) may increase or decrease. The magnetic field is in vertical direction and also we don’t know it is upward or downward. According to Flemings left hand rule the force will act either inward or outward. So option D is correct.
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