Physics MCQs for NEET — Practice Questions with Answers

As stated in the 'INTRODUCTION' section, 'When an external force does work in taking a body from a point to another against a force like spring force or gravitational force, that work gets stored as potential energy of the body.'

The NCERT text defines, 'Potential energy of the system = the total work done in assembling the configuration.' (Equation 2.29 and point 6 in summary)

According to Eq. (2.28), 'Work done in bringing $q_2$ to $r_2$ is $q_2V(r_2) + \frac{1}{4\pi\epsilon_0}\frac{q_1q_2}{r_{12}}$'. This accounts for work against both the external field and the field of $q_1$.

According to the NCERT text, 'Action and reaction act on different bodies and so they cannot be cancelled out.' This is a common misconception, as forces can only cancel when acting on the same body.

The expulsion of air (action) creates a thrust force on the balloon in the opposite direction (reaction), causing it to move. This is a direct application of Newton's Third Law: 'To every action, there is always an equal and opposite reaction'.

The NCERT states, 'Force on a body A by body B is equal and opposite to the force on the body B by A.' When the person pushes the ground backward (action), the ground pushes the person forward (reaction), enabling them to move.

The NCERT text explicitly states, 'Force on a body A by body B is equal and opposite to the force on the body B by A'. This means the forces have the same magnitude but act in opposite directions, represented by the negative sign in the vector equation.

The NCERT states, 'Any of the two mutual forces can be called action and the other reaction. Action and reaction forces are simultaneous forces. There is no cause-effect relation between action and reaction.' This clarifies that 'action' does not imply precedence or causality in physics.

An action-reaction pair involves forces between two interacting bodies. When a person pushes a wall, the wall simultaneously pushes back on the person with an equal and opposite force. The other options describe forces acting on a single body or a single force component.

The NCERT text clearly states, 'Action and reaction act on different bodies and so they cannot be cancelled out.' For forces to cancel, they must act on the same body.