Q. Binding energy per nucleon for helium nucleus ${(}_2^{4}He)$ is 7.0 MeV. Find vallue of mass defect for helium nucleus.

Q. When a beam of white light is passed through sodium vapours and then through a spectrometer, spectrum so obtained has two dark lines present in the yellow region. This spectrum is called

1. band spectrum
2. emission spectrum of sodium
3. absorption spectrum of sodium
4. continuous spectrum

Q. Define temperature coefficient of resistance of the material of a conductor.

Q. Intensity of electric field at a point at a perpendicular distance 'r' from an infinite line charge, having linear charge density '$\lambda$' is given by :

1. $E=\left(\frac{1}{4\pi {ϵ}_0}\right)\frac{2\lambda }{r}$
2. $E=\left(\frac{1}{4\pi {\epsilon }_0}\right)\frac{\lambda }{r^2}$
3. $E=\left(\frac{1}{4\pi {\epsilon }_0}\right)\frac{\lambda }{r}$
4. $E=\left(\frac{1}{4\pi {\epsilon }_0}\right)\frac{2\lambda }{r^2}$

Q. If $l_3$ and $l_2$ represent angular momenta of an orbiting electron in III and II Bohr orbits respectively, then $l_3:l_2$ is

1. 3 : 2
2. 9 : 4
3. 2 : 3
4. 4 : 9

Q. A ray of light is incident on a transparent medium at polarizing angle. What is the angle between the reflected ray and the refracted ray?

Q. Draw the truth table of a NOR gate.

Q. Draw labelled circuit diagram of a potentiometer to compare emfs of two cells.
Write the working formula (Derivation not required).

Q. When the cold junction of a thermocouple is maintained at 0${}^o$C, the thermo emf 'e', generated by this thermocouple is given by the relation.

Q. Find the emf of the battery shown in figure

Q. So that the torque acting on it is zero.

Q. Your are provided with 8$\mu$F capacitors. Show with the help of a diagram how you will arrange minimum number of them to get a resultant capacitance of 20 $\mu$F.

Q. At a certain temperature, a ferromagnetic material becomes paramagnetic. What is this temperature called?

Q. A metallic wire having length of $2m$ and weight of $4\times {10}^{-3}N$ is found to remain at rest in a uniform and transverse magnetic field $2\times {10}^{-4}T$. Current flowing through the wire is

1. 10 A
2. 5 A
3. 2 A
4. 1 A

Q. So that the torque acting on it is maximum.

Q. Write one balanced reaction representing nuclear fusion.

Q. What is the colour code of a corbon resistor having a resistance of 470 $\Omega$ and a tolerance of 5%?

Q. Half life of a certain radioactive element is 3.465 days. Find its disintegration constant.

Q. With reference to photo-electric effect, what is mean by threshold wavelength?

Q. When does a moving charged particle not experience any force while moving through a uniform magnetic field?

Q. Two substances A and B have their relative permeabilities slightly greater and slightly less than 1 respectively. What do you conclude about A and B as far as their magnetic materials are concerned?

Q. With reference to free electron theory of conductivity, explain the terms
(a) Drift speed
(b) Relaxation time

Q. A parallel plate air capacitor has a capacitance of 5$\mu F$. It becomes 50 $\mu F$ when a dielectric medium occupies the entire space between its two plates.
What is the dielectric constant of the medium?

Q. If $R_1$ and $R_2$ are filament resistances of a 200 W and a 100 W bulb respectively, designed to operate on the same voltage, then:

1. $R_1=R_2$
2. $R_2=4R_1$
3. $R_2=2R_1$
4. $R_1=4R_2$

Q. How does focal length of a convex lens change with increase in wavelength of incident light?

Q. What is the turns ratio i.e., transformer ratio, $n_s:n_p$, in an ideal transformer which increases ac voltage from 220 V to 33000 V?

Q. How much resistance should be connected to 15$\Omega$ resistor shown in the circuit in adjoining figure below so that the points M and N are at the same potential.

Q. Name the physical principle on which the working of optical fibres is based.

Q. What is meant by coherent sources of light?