Q. An induced current has no direction of its own. Explain. why?

Q. For a common emitter amplifier. dc(direct current) current gain is $100$. If the base current is $20\mu$A, calculate the collector and emitter current.

Q. (a) What is least distance of distinct vision for a normal human eye?
(b) With the help of labelled diagram. give the principle and magnifying power of astronomical telescope when final image is formed at least distance of distinct vision.

Q. (a) Define one tesla.
(b) Derive an expression for force experienced by a current carrying straight conductor placed in a magnetic field. How can we find the direction of force?

Q. Name the three basic elements of a communication system.

Q. What type of magnetic material is used in making electromagnets and why?

Q. (a) What are characteristics of image formed by a plane mirror?
(b) By giving sign conventions made, derive the mirror formula for a concave mirror.

Q. Which has greater ionising power : alpha particle or beta particle?

Q. Why sky wave propagation is not possible for high frequency radio waves?

Q. (a) What is shunt?
(b) State Ampere's circuital law. Using the law, obtain an expression for the magnetic field well aside the solenoid of finite length.

Q. Write the following radiations in an ascending order in respect of their frequencies : X- rays, microwaves, UV (ultra - violet) rays and radio waves.

Q. Write whether the given statement is true or false : The magnetic susceptibility $\left(X_m\right)$ of a paramagnetic substance has a small negative value.

Q. Light of wavelength $2200A^o$ (angstorm) falls on a photosensitive plate with work function $4.1$ eV. Find (a) energy of photon in eV (electron volt). (b) maximum kinetic energy of photoelectron and (c) stopping potential.

Q. Obtain the equivalent capacitance of the network in given figure. For a $300V$ supply, determine the charge across capacitor $C_4$.

Q. Derive an expression for energy stored in a capacitor. In which form energy is stored?

Q. With the help of circuit diagram, explain the V-1 characteristics of p-n junction diode in forward biasing.

Q. State radioactive decay law. Prove that radioactive decay is exponential in nature.

Q. State Huygen's principle. Using Huygen's wave theory, prove the laws of reflection.

Q. (a) Which physical quantity has its SI unit (1) Cm (2) N/C.
(b) Two point charges q and -q is placed at a distance $2a$ apart. Calculate the electric field at a point P is situated at a distance r along the perpendicular bisector of the line joining the charges. What is the electric field when r >> a? Also, give the direction of electric field w.r.t. electric dipole moment?

Q. With the help of a circuit diagram, explain how a metre bridge can be used to find the unknown resistance of a given wire.

Q. State Lenz's law of electromagnetic induction.

Q. (a) A charged rod P attracts rod R whereas P repels another charged rod Q. What type of force is developed between Q and R?
(b) Define the capacitance of capacitor. Derive and expression for the capacity at a parallel plate capacitor with a dielectric slab placed in between the plates of capacitor.

Q. What is photoelectric effect? Explain the effect of increase (i) frequency (ii) intensity of incident radiation on photoelectric current with suitable graphs.

Q. Write the conditions for total internal reflection to take place.

Q. An electron of mass 'm' and charge 'e' is accelerated from rest through a potential difference 'V' in vacuum. Its final velocity will be

1. $\frac{eV}{2m}$
2. $\frac{eV}{m}$
3. $\sqrt{\frac{2eV}{m}}$
4. $\sqrt{\frac{eV}{m}}$

Q. In Young's double slit experiment, the slits are separated by $0.56$ mm and the screen is placed $2.8$ cm away. The distance between the central bright fringe and the fifth bright fringe is $1.5$cm. Find the wavelength of light used.

Q. A wire has a resistance of $10.5\Omega$ at ${21}^{o}C$ and $16.4\Omega$ at ${147}^{o}C$. Find the value of temperature coefficient of resistance.

Q. The small ozone layer on top of the stratosphere is crucial for human survival. Why?

Q. Derive an expression for average power of an AC (alternating current) circuit.