The cylindrical tube of a spray pump has a cross-section of $$8$$ cm2 one end of which has $$40$$ fine holes each of area $$10^{-8}$$ m2. If the liquid flows inside the tube with a speed of $$0.15$$ m min-1 the speed with which the liquid is ejected through the holes is:
1. $$50$$ m/s
2. $$5$$ m/s
3. $$0.05$$ m/s
4. $$0.5$$ m/s
Subtopic:  Equation of Continuity |
59%
Hints

Which one of the following graphs represents the variation of maximum kinetic energy $$(E_k)$$ of the emitted electrons with frequency $$\nu$$ in photoelectric effect correctly?

 1 2 3 4
Subtopic:  Einstein's Photoelectric Equation |
Hints

A vessel of height $$2~d$$ is half filled with a liquid of refractive index $$\sqrt2$$ and the other half with a liquid of refractive index $$n$$ (the given liquids are immiscible). Then, the apparent depth of the inner surface of the bottom of the vessel (neglecting the thickness of the bottom of the vessel) will be:
1. $$\frac{n}{d(n+\sqrt{2})}$$
2. $$\frac{d(n+\sqrt{2})}{n \sqrt{2}}$$
3. $$\frac{\sqrt{2} n}{d(n+\sqrt{2})}$$
4. $$\frac{n d}{d+\sqrt{2} n}$$

Subtopic:  Refraction at Plane Surface |
58%
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A shell of mass $$20$$ kg at rest explodes into two fragments whose masses are in the ratio $$2:3.$$ The smaller fragment moves with a velocity of $$6$$ m/s. The kinetic energy of the larger fragment is:
1. $$96$$ J
2. $$216$$ J
3. $$144$$ J
4. $$360$$ J

Subtopic:  Collisions |
57%
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An electric bulb has a rated power of $$50$$ W at $$100$$ V. If it is used on an AC source $$200$$ V, $$50$$ Hz, a choke has to be used in series with it. This choke should have an inductance of:
1. $$0.1$$ mH
2. $$1$$ mH
3. $$0.1$$ H
4. $$1.1$$ H

Subtopic:  Self - Inductance |
Hints

In Young's double slit experiment with sodium vapour lamp of wavelength $$589$$ nm and the slits $$0.589$$ mm apart, the half angular width of the central maximum is:
1. $$sin^{-1} (0.01)$$
2. $$sin^{-1} (0.0001)$$
3. $$sin^{-1} (0.001)$$
4. $$sin^{-1} (0.1)$$

Subtopic:  Young's Double Slit Experiment |
61%
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A parallel plate capacitor with air as the dielectric has capacitance $$C.$$ A slab of dielectric constant $$K$$ having the same thickness as the separation between the plates is introduced so as to fill one-fourth of the capacitor as shown in the figure. The new capacitance will be:

1. $$(K+3)\frac C4$$
2. $$(K+2)\frac C4$$
3. $$(K+1)\frac C4$$
4. $$\frac{KC}{4}$$

Subtopic:  Dielectrics in Capacitors |
54%
Hints

Three concurrent co-planar forces $$1$$ N, $$2$$ N and $$3$$ N acting along different directions on a body.
Choose the correct statement:

 1 can keep the body in equilibrium if $$2$$ N and $$3$$ N act at right angle. 2 can keep the body in equilibrium if $$1$$ N and $$2$$ N act at right angle. 3 cannot keep the body in equilibrium. 4 can keep the body in equilibrium in $$1$$ N and $$3$$ N acts at an acute angle.

Subtopic:  Resultant of Vectors |
55%
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The work done by force acting on a body is as shown in the graph. The total work done in covering an initial distance of $$20$$ m is:

1. $$212.5$$ J
2. $$200$$ J
3. $$400$$ J
4. $$175$$ J

Subtopic:  Work Done by Variable Force |
Horizontal tube of non-uniform cross-section has radii of $$0.1$$ m and $$0.05$$ m respectively at M and N. For a streamlined flow of the liquid, the rate of liquid flow is: