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.

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. $\frac{n d}{d+\sqrt{2} n}$

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

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. $\frac{KC}{4}$

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

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

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: