AP EAMCET201921 Apr 2019Evening ShiftPhysicsWork, Power and EnergyActual
Assertion A : The work done by the electrostatic force is zero when a point charge moves in a circular path around another charge. Reason R : The dot product of force and displacement vectors gives work done.
Options
- ABoth Assertion and Reason are true and Reason is the correct explanation of Assertion.
- BBoth Assertion and Reason are true but Reason is NOT the correct explanation of Assertion.
- CAssertion is true but Reason is false.
- DAssertion is false but Reason is true.
Correct answer
A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Step-by-step solution
When the force is acting at right angle to the direction of motion of charge, then the work done is zero. W = F d cos 90 ° W = 0 The electrostatic force is radially inwards when a point charge moves in a circular path around another charge. Therefore, the electrostatic force acts at right angle to the direction of motion of the charge. Hence, work done is zero.