JEE MAIN - Physics (2017 - 9th April Morning Slot - No. 14)
A negative test charge is moving near a long straight wire carrying a current. The force acting on the test charge is parallel to the direction of the current. The motion of the charge is :
away from the wire
towards the wire
parallel to the wire along the current
parallel to the wire opposite to the current
설명
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Given situation is shown in the figure
As we know,
$$\overrightarrow F = q(\overrightarrow v \times \overrightarrow B )$$
$$\overrightarrow F = - {q_0}(\overrightarrow v \times \overrightarrow B )$$
According to question, direction of current is parallel to the force acting on the electron. Hence, the motion of test charge is towards the wire.