The current in an inductor of self-inductance \(4~\text{H}\) changes from \(4~ \text{A}\) to \(2~\text{A}\) in \(1~ \text s\). The emf induced in the coil is:
1. \(-2~\text{V}\)
2. \(2~\text{V}\)
3. \(-4~\text{V}\)
4. \(8~\text{V}\)
The correct statement about the variation of viscosity of fluids with an increase in temperature is:
| 1. | viscosity of gases decreases. |
| 2. | viscosity of both liquids and gases increases. |
| 3. | viscosity of liquids increases. |
| 4. | viscosity of liquids decreases. |
The de-Broglie wavelength of the thermal electron at \(27^\circ \text{C}\) is \(\lambda.\) When the temperature is increased to \(927^\circ \text{C},\) its de-Broglie wavelength will become:
| 1. | \(2\lambda\) | 2. | \(4\lambda\) |
| 3. | \(\dfrac\lambda2\) | 4. | \(\dfrac\lambda4\) |
Assuming the earth to be a sphere of uniform density, its acceleration due to gravity acting on a body:
| 1. | increases with increasing altitude. |
| 2. | increases with increasing depth. |
| 3. | is independent of the mass of the earth. |
| 4. | is independent of the mass of the body. |
1. \(3:1\)
2. \(1:4\)
3. \(1:1\)
4. \(1:3\)
During simple harmonic motion of a body, the energy at the extreme position is:
| 1. | both kinetic and potential |
| 2. | is always zero |
| 3. | purely kinetic |
| 4. | purely potential |
A fluid of density \(\rho~\)is flowing in a pipe of varying cross-sectional area as shown in the figure. Bernoulli's equation for the motion becomes:
1. \(p+\dfrac12\rho v^2+\rho gh\text{ = constant}\)
2. \(p+\dfrac12\rho v^2\text{ = constant}\)
3. \(\dfrac12\rho v^2+\rho gh\text{ = constant}\)
4. \(p+\rho gh\text{ = constant}\)
The ratio of the moments of inertia of two spheres, about their diameters, having the same mass and their radii being in the ratio of \(1:2\), is:
| 1. | \(2:1\) | 2. | \(4:1\) |
| 3. | \(1:2\) | 4. | \(1:4\) |
| Assertion (A): | A standing bus suddenly accelerates. If there was no friction between the feet of a passenger and the floor of the bus, the passenger would move back. |
| Reason (R): | In the absence of friction, the floor of the bus would slip forward under the feet of the passenger. |
| 1. | (A) is True but (R) is False. |
| 2. | (A) is False but (R) is True. |
| 3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 1. | \(60^\circ\) | 2. | \(75^\circ\) |
| 3. | \(30^\circ\) | 4. | \(45^\circ\) |
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