Two blocks of masses $m$ and $M$, ($M > m$), are placed on a frictionless table as shown in figure. A massless spring with spring constant $k$ is attached with the lower block. If the system is slightly displaced and released, then

A. The time period of small oscillation of the two blocks is $T = 2\pi \sqrt{\frac{(m+M)}{k}}$ 

B. The acceleration of the blocks is $a = \frac{kx}{M+m}$ (x = displacement of the blocks from the mean position) 

C. The magnitude of the frictional force on the upper block is $\frac{\mu m|x|}{M+m}$ 

D. The maximum amplitude of the upper block, if it does not slip, is $\frac{\mu (M+m)g}{k}$ 

E. Maximum frictional force can be $\mu(M + m) g$. 

Choose the correct answer from the options given below:

A parallel plate capacitor is filled equally(half) with two dielectrics of dielectric constants $\varepsilon_1$ and $\varepsilon_2$, as shown in figures. The distance between the plates is $d$ and area of each plate is $A$. If capacitance in first configuration and second configuration are $C_1$ and $C_2$ respectively, then $\frac{C_1}{C_2}$ is :

First Configuration 

The electrostatic potential on the surface of uniformly charged spherical shell of radius $R = 10 \ cm$ is $120 \ V$. The potential at the centre of shell, at a distance $r = 5 \ cm$ from centre, and at a distance $r = 15 \ cm$ from the centre of the shell respectively, are:

The radiation pressure exerted by a $450 \ W$ light source on a perfectly reflecting surface placed at $2m$ away from it, is

A loop ABCDA, carrying current I = 12 A, is placed in a plane, consists of two semi-circular segments of radius $R_1 = 6\pi$ m and $R_2 = 4\pi$ m. The magnitude of the resultant magnetic field at center O is $k\times10^{-7}$ T. The value of k is __________ 

(Given $\mu_0 = 4\pi \times 10^{-7}$ Tm $A^{-1}$)

A small bob of mass 100 mg and charge $+10 \text{ }\mu C$ is connected to an insulating string of length 1 m. It is brought near to an infinitely long non-conducting sheet of charge density '$\sigma$' as shown in figure. If string subtends an angle of $45^\circ$ with the sheet at equilibrium the charge density of sheet will be. 
(Given, $\epsilon_0 = 8.85\times10^{-12} \frac{F}{m}$ and acceleration due to gravity, $g=10 \frac{m}{s^2}$)

The relationship between the magnetic susceptibility ($\chi$) and the magnetic permeability ($\mu$) is given by : 
($\mu_0$ is the permeability of free space and $\mu_r$ is relative permeability)

Consider two infinitely large plane parallel conducting plates as shown below. The plates are uniformly charged with a surface charge density $+ \sigma$ and $- 2\sigma$. The force experienced by a point charge $+ q$ placed at the mid point between two plates will be :

Two blocks of masses $m$ and $M$, ($M > m$), are placed on a frictionless table as shown in figure. A massless spring with spring constant $k$ is attached with the lower block. If the system is slightly displaced and released, then

A. The time period of small oscillation of the two blocks is $T = 2\pi \sqrt{\frac{(m+M)}{k}}$ 

B. The acceleration of the blocks is $a = \frac{kx}{M+m}$ (x = displacement of the blocks from the mean position) 

C. The magnitude of the frictional force on the upper block is $\frac{\mu m|x|}{M+m}$ 

D. The maximum amplitude of the upper block, if it does not slip, is $\frac{\mu (M+m)g}{k}$ 

E. Maximum frictional force can be $\mu(M + m) g$. 

Choose the correct answer from the options given below:

A parallel plate capacitor is filled equally(half) with two dielectrics of dielectric constants $\varepsilon_1$ and $\varepsilon_2$, as shown in figures. The distance between the plates is $d$ and area of each plate is $A$. If capacitance in first configuration and second configuration are $C_1$ and $C_2$ respectively, then $\frac{C_1}{C_2}$ is :

First Configuration 

The electrostatic potential on the surface of uniformly charged spherical shell of radius $R = 10 \ cm$ is $120 \ V$. The potential at the centre of shell, at a distance $r = 5 \ cm$ from centre, and at a distance $r = 15 \ cm$ from the centre of the shell respectively, are:

The radiation pressure exerted by a $450 \ W$ light source on a perfectly reflecting surface placed at $2m$ away from it, is