Q. The dimensional formula of $\sqrt{{\mu }_r{\in }_r}$ is _______?

1. $M^1{L}^{-1}{T}^{-2}{A}^{-1}$
2. $M^1{L}^1{T}^{-2}{A}^0$
3. $M^0{L}^0{T}^0{A}^0$
4. $M^0{L}^2{T}^{-2}{A}^0$

Q. At large distances from source $\overrightarrow{E}$ and $\overrightarrow{B}$ are in phase and the decrease in their magnitude is comparatively slower with distance r as per __________.

1. $r^{-1}$
2. r
3. $r^{-3}$
4. $r^2$

Q. The angular spread of central maximum, in diffraction pattern, does not depend on ________.

1. The distance between the slit and source
2. Width of slit
3. Wavelength of light
4. Frequency of light

Q. The ratio of resolving power of telescope, when lights of wavelength $4400\stackrel{o}{A}$ and $5500\stackrel{o}{A}$ are used, is _________.

1. $16:25$
2. $4:5$
3. $9:1$
4. $5:4$

Q. In Young's experiment fourth bright fringe produced by light of $5000\stackrel{o}{A}$ superposes on the fifth bright fringe of an unknown wavelength. The unknown wavelength is _________$\stackrel{o}{A}$.

1. $4000$
2. $6000$
3. $5000$
4. $8000$

Q. In X-ray tube the potential difference between the anode and the cathode is $20$kV and the current flowing is $1.6$mA. The number of electrons striking the anode in $1$s is ________.(Charge of an electron$=1.6\times {10}^{-19}C$)

1. ${10}^{14}$
2. $1.25\times {10}^{16}$
3. ${10}^{16}$
4. $6.25\times {10}^{18}$

Q. If the kinetic energy of the electron in the hydrogen atoms is $\frac{e^2}{8\pi {\in }_{0}r}$, then its potential energy is ________.

1. $\frac{e^2}{4\pi {\in }_{0}r}$
2. $-\frac{e^2}{4\pi {\in }_{0}r}$
3. $\frac{e^2}{8\pi {\in }_{0}r}$
4. $-\frac{e^2}{8\pi {\in }_{0}r}$

Q. The wavelength of the first line of Lyman series is $\lambda$. The wavelength of the first line in Paschen series is ________.

1. $108/7$
2. $27/5$
3. $7/108$
4. $5/27$

Q. For a radioactive element, $\tau =$ _______${\tau }_{1/2}$.

1. $0.693$
2. $693$
3. $144$
4. $1.44$

Q. For the following nuclear disintegration process ${}_{92}^{238}U\to {}_{82}^{206}Pb+x{[}_2^{4}He]+{[}_{-2}^{0}e]$ then value of x is _______.

1. $8$
2. $6$
3. $4$
4. $10$

Q. If the radii of ${}_{30}^{64}Zn$ and ${}_{13}^{27}Al$ nuclei are $R_1$ and $R_2$ respectively then $\frac{R_1}{R_2}=$ _________.

1. $\frac{64}{27}$
2. $\frac{4}{3}$
3. $\frac{3}{4}$
4. $\frac{27}{64}$

Q. For PN junction, the intensity of electric field is $1\times {10}^6$ V/m and the width of depletion region is $5000\stackrel{o}{A}$. The value of potential barrier$=$_______V.

1. $0.05$
2. $0.005$
3. $0.5$
4. $5$

Q. The logic circuit in the figure represents characteristics of which logic gate?

1. NOR
2. OR
3. NAND
4. NOT

Q. A modulating signal of frequency $5$ kHz and peak voltage of $8$V is used to modulate a carrier of frequency $10$ MHz and peak voltage $10$V. Then the amplitude of USB is _________V.

1. $3$
2. $4$
3. $2$
4. $5$

Q. The propagation of radio waves with frequency $2$ MHz to $30$ MHZ is due to _______.

1. Space wave
2. Optical wave
3. Ground wave
4. Sky wave

Q. When two spheres having $4Q$ and $-2Q$ charge are placed at a certain distance, the force acting between them is F. Now they are connected by a conducting wire and again separated from each other. Now they are kept at a distance half of the previous one. The force acting between them is _______.

1. F
2. $F/4$
3. $F/2$
4. $F/8$

Q. Charge of $1\mu C$ each is placed on the five corners of a regular hexagon of side $1$m. The electric field at its centre is _______N/C.

1. $\frac{5}{6}\times {10}^{-6}$K
2. $5\times {10}^{-6}$K
3. $\frac{6}{5}\times {10}^{-6}$K
4. ${10}^{-6}$K

Q. An electric dipole is placed in a non-uniform electric field, then _______.

1. The resultant force acting on the dipole is always zero
2. Torque acting on it may be zero
3. The resultant force acting on the dipole may be zero
4. Torque acting on it is always zero

Q. The unit of intensity of polarization is _______.

1. $C/m^2$
2. $C^2/m^2$
3. $C^2/m$
4. $m^2/C$

Q. In the figure area of each plate is A and the distance between consecutive plates is as shown in the figure. What is the effective capacitance between points A & B.

1. $\frac{A{\epsilon }_0}{d}$
2. $\frac{3A{\epsilon }_0}{d}$
3. $\frac{2A{\epsilon }_0}{d}$
4. $\frac{4A{\epsilon }_0}{d}$

Q. A moving positive charge approaches a negative charge. What will happen to the potential energy of the system?

1. Will remain constant
2. Will decrease
3. Will increase
4. May increase or decrease

Q. The heat produced per unit time, on passing an electric current through a conductor at a given temperature, is directly proportional to the _______.

1. Electric current
2. Reciprocal of electric current
3. Square of electric current
4. Reciprocal of square of electric current

Q. A carbon resistor has three bands ad brown, black and green in order. What will be the range of resistance it offers.

1. $7\times {10}^5\Omega -13\times {10}^5\Omega$
2. $9\times {10}^5\Omega -11\times {10}^5\Omega$
3. $8\times {10}^5\Omega -12\times {10}^5\Omega$
4. None of these

Q. In the network shown in the figure the equivalent resistance between points X & Y will be ________$\Omega$. Value of each resistance is $2\Omega$.

1. $2$
2. $4$
3. $1$
4. $2/3$

Q. Shunt wire should be _______.

1. Thick and long
2. Thick and short
3. Thin and long
4. Thin and short

Q. The dimensional formula of effective torsional constant of spring is ________.

1. $M^1{L}^2{T}^{-3}$
2. $M^1{L}^2{T}^{-2}{A}^{-2}$
3. $M^1{L}^2{T}^{-2}$
4. $M^0{L}^0{T}^0$

Q. There are $50$ turns per cm length in a very long solenoid. It carries a current of $2.5$A. The magnetic field at its centre on the axis is _______ T.

1. $5\pi \times {10}^{-3}$
2. $6\pi \times {10}^{-3}$
3. $2\pi \times {10}^{-3}$
4. $4\pi \times {10}^{-3}$

Q. The gyromagnetic ratio of an electron $=$__________ specific charge of an electron.

1. $1$
2. $2$
3. $1/2$
4. $4$

Q. Alnico is an alloy of _______.

1. Ai, Ni, Cu, P
2. Al, Ni, Cu, Co
3. Al, Ni, As, O
4. Al, As, P, Pt

Q. The focal length of a thin lens made from the material of refractive index $1.5$ is $15$cm. When it is placed in a liquid of refractive index $4/3$, its focal length will be ________cm.

1. $80.31$
2. $50$
3. $78.23$
4. $60$