The current in an inductor of self-inductance \(4~\mathrm{H}\) changes from \(4~ \mathrm{A}\) to \(2~\mathrm{A}\) in \(1~ \mathrm s\) . The e.m.f. induced in the coil is:
1. \(-2~\mathrm V\)
2. \(2~\mathrm V\)
3. \(-4~\mathrm V\)
4. \(8~\mathrm V\)
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 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. \(\frac\lambda2\)
4. \(\frac\lambda4\)
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. |
A particle of mass \(4M\) kg at rest splits into two particles of mass \(M\) and \(3M.\) The ratio of the kinetic energies of mass \(M\) and \(3M\) would be:
| 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. \(p+\frac12\rho v^2+\rho gh\text{=constant}\)
2. \(p+\frac12\rho v^2\text{=constant}\)
3. \(\frac12\rho v^2+\rho gh\text{=constant}\)
4. \(p+\rho gh\text{=constant}\)
The ratio of the moments of inertia of two spheres about their diameter and having same mass and their radii 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). |
A linearly polarized monochromatic light of intensity \(10\) lumen is incident on a polarizer. The angle between the direction of polarization of the light and that of the polarizer such that the intensity of output light is \(2.5\) lumen is:
1. \(60^\circ\)
2. \(75^\circ\)
3. \(30^\circ\)
4. \(45^\circ\)
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