Write two important advantages of reflecting telescope over a refracting telescope.

Concept: Optical Instruments - Telescope

State the two Kirchhoff’s rules used in electric networks. How are there rules justified?

Concept: Kirchhoff’s Rules

Answer the following questions:

In a single slit diffraction experiment, the width of the slit is made double the original width. How does this affect the size and intensity of the central diffraction band?

Concept: Diffraction - The Single Slit

Give the truth table and circuit symbol for NAND gate

Concept: Digital Electronics and Logic Gates

Define electric flux.

Concept: Electric Flux

If the point charge is now moved to a distance 'd' from the centre of the square and the side of the square is doubled, explain how the electric flux will be affected.

Concept: Applications of Gauss’s Law

Use Gauss' law to derive the expression for the electric field `(vecE)`due to a straight uniformly charged infinite line of charge density λ C/m.

Concept: Applications of Gauss’s Law

Draw a graph to show the variation of E with perpendicular distance r from the line of charge.

Concept: Applications of Gauss’s Law

Find the work done in bringing a charge q from perpendicular distance r_{1} to r_{2} (r_{2} > r_{1})

Concept: Applications of Gauss’s Law

Four point charges Q, q, Q and q are placed at the corners of a square of side 'a' as shown in the figure.

Find the

1) resultant electric force on a charge Q, and

2) potential energy of this system.

Concept: Potential Energy of a System of Charges

Two electric bulbs P and Q have their resistances in the ratio of 1 : 2. They are connected in series across a battery. Find the ratio of the power dissipation in these bulbs

Concept: Combination of Resistors – Series and Parallel

A 10 V cell of negligible internal resistance is connected in parallel across a battery of emf 200 V and internal resistance 38 Ω as shown in the figure. Find the value of current in the circuit.

Concept: Cells, Emf, Internal Resistance

Define the term 'conductivity' of a metallic wire. Write its SI unit.

Concept: Electrical Resistivity and Conductivity

A proton and an electron travelling along parallel paths enter a region of uniform magnetic field, acting perpendicular to their paths. Which of them will move in a circular path with higher frequency?

Concept: Motion in Combined Electric and Magnetic Fields - Cyclotron

A bar magnet of magnetic moment 6 J/T is aligned at 60° with a uniform external magnetic field of 0·44 T Calculate

a) the work done in turning the magnet to align its magnetic moment

i) normal to the magnetic field,

ii) opposite to the magnetic field, and

b) the torque on the magnet in the final orientation in case (ii).

Concept: Magnetic Diapole

An iron ring of relative permeability µ_{r} has windings of insulated copper wire of n turns per meter. When the current in the windings is I, find the expression for the magnetic field in the ring.

Concept: Solenoid and the Toroid - the Toroid

The susceptibility of a magnetic material is 0·9853. Identify the type of magnetic material. Draw the modification of the field pattern on keeping a piece of this material in a uniform magnetic field.

Concept: Magnetic Properties of Materials

State the principle of an ac generator and explain its working with the help of a labelled diagram. Obtain the expression for the emf induced in a coil. having N turns each of cross-sectional area A, rotating with a constant angular speed 'ω' in a magnetic field `vecB` directed perpendicular to the axis of rotation.

Concept: Ac Generator

An aeroplane is flying horizontally from west to east with a velocity of 900 km/hour. Calculate the potential difference developed between the ends of its wings having a span of 20 m. The horizontal component of the Earth's magnetic field is 5 × 10^{–4} T and the angle of dip is 30°.

Concept: Induced Emf and Current