Technical Based Test Test 1 Nddc Scholarship

Correct answer: (c) both (a) and (b)

Moment of inertia depends on the mass of the body and how that mass is distributed relative to the chosen axis of rotation.

Correct answer: (c) both (a) and (b)

Moment of inertia depends on the mass of the body and how that mass is distributed relative to the chosen axis of rotation.

Correct answer: (a) rotational K.E. of the body

Work done by a torque causes angular acceleration, leading to a change in the body’s rotational kinetic energy.

Correct answer: (b) \(p = \dfrac{3T}{r}\)

For a soap bubble, there are two liquid surfaces, so the excess pressure is \(p = \dfrac{4T}{r}\) for a drop and \(p = \dfrac{3T}{r}\) when considering the combined effect of the two surfaces and air inside.

Correct answer: (d) viscous force

In some fluids like gases, viscosity — and thus viscous force — increases with temperature.

Derivation of the dimensional formula of potential difference:

\[V = \dfrac{\text{Work done}}{\text{Charge}}\]\[[\text{Work}] = [\text{Energy}] = M L^2 T^{-2}\]\[[\text{Charge}] = [\text{Current}] \times [\text{Time}] = A \, T\]\[[V] = \dfrac{M L^2 T^{-2}}{A \, T}\]\[[V] = M L^2 T^{-3} A^{-1}\]Dimensional formula of potential difference\[M L^2 T^{-3} A^{-1}\] 

Correct answer: (a) zero

Surface tension decreases with temperature and becomes zero at the boiling point of the liquid.

Correct answer: (c) Lenz’s law

Lenz’s law explains that the induced current opposes the change causing it, meaning the mechanical energy supplied is converted into electrical energy stored in the coil.

Correct answer: (a) directly on time

From Joule’s law, H = I²Rt, heat produced is directly proportional to the time current flows.

Correct answer: (a) surface tension of Dettol is greater than that of water

Greater surface tension allows Dettol to effectively penetrate and clean fine cavities in wounds.