Q. Write down the relation between $\alpha$ and $\beta$ related to amplifier.

Q. Write down four differences between interference and diffraction :

Q. A T.V. antenna is of height $h$ metre. Show that it can be used to transmit the signal up to the distance $d=\sqrt{2hR}$ on the earth surface, where $R$ is the radius of earth.

Q. What is reflection? Write the laws of reflection.

Q. Unit of specific resistance is

1. ${ohm}^{-1}$
2. $ohm$
3. $ohm$ $metre$
4. ${ohm}^{-1}$ ${metre}^{-1}$

Q. What are de-Broglie waves? Establish the de-Broglie wavelength equation.

Q. What is the value of specific charge of an electron?

Q. $1eV=$ _________ Joule.

Q. Select the appropriate option from column 'B' for each statement of column 'A' and match the correct pair.

Q. What is "Photoelectric Effect"?

Q. Who invented the television ?

Q. Describe the astronomical telescope on the basis of the following points:
(i) Labelled ray diagram.
(ii) Derivation of formula for magnifying power, when final image is formed at the least distance of distinct vision.

Q. Write the S.I. unit of capacitance.

Q. The device which converts the mechanical energy in to electric energy is

1. D.C. motor
2. A.C. dynamo
3. Transformer
4. Starter

Q. Two point charges, each of charge $q$, are placed at a separation of $2a$. The electric potential at their midpoint will be :

1. Zero
2. $\frac{q}{8\pi {\epsilon }_{0}a}$
3. $\frac{q}{2\pi {\epsilon }_{0}a}$
4. $\frac{q}{2\pi {\epsilon }_0{a}^2}$

Q. The distance from the pole of a spherical mirror to its focus is called _______ of that mirror.

Q. Describe the compound microscope on the following headings:
(i) Labelled ray diagram of formation of image.
(ii) Magnifying power when final image is formed at least distance of distinct vision.

Q. Derive expression for the self inductance of a solenoid. What factors affect it?

Q. In which of the following LASER is used?

1. Radar
2. Long distance measurement
3. Meteorology
4. All of the above

Q. The frequency of optical waves is of the order of ________.

Q. State Biot-Savart's law? Define the unit of current.

Q. The ozonosphere absorbs the

1. Microwaves
2. Visible light
3. Ultraviolet radiations
4. Infrared radiation

Q. How is a $P$-type semi conductor formed?

Q. The use of zener diode is as ________.

Q. Write the name of the radiations of shortest and longest wavelength in the electromagnetic spectrum.

Q. For measuring the current in a circuit, the instrument used is

1. Ammeter
2. Voltameter
3. Voltmeter
4. Galvanometer

Q. Derive expression for the intensity of magnetic field at a point in end on position due to a short bar magnet.

Q. What is meant by magnification of a lens? Write its expression.

Q. Obtain expression for an a.c. circuit:
$P_{av}=V_{rms}\times I_{rms}\cos \varphi$

Q. What is demodulation?