Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Physics

A coil of radius 10 cm and resistance 40 Ω has 1000 turns. It is placed with its plane vertical and its axis parallel to the magnetic meridian. The coil is connected to a galvanometer and is rotated about the vertical diameter through an angle of 180°. Find the charge which flows through the galvanometer if the horizontal component of the earth's magnetic field is B_H = 3.0 × 10⁻⁵ T.

The figure show a network of five capacitors connected to a 10V battery. Calculate the charge acquired by the 5μF capacitor.

State how a moving coil galvanometer can be converted into an ammeter.

Explain the significance of a radial magnetic field when a current-carrying coil is kept in it. 

Draw the circuit arrangement for studying the output characteristics of n-p-n transistor in CE configuration. Explain how the output characteristics are obtained.

Three circuits, each consisting of a switch 'S' and two capacitors, are initially charged, as shown in the figure. After the switch has been closed, in which circuit will the charge on the left-hand capacitor
(i) increase,
(ii) decrease, and
(iii) remains the same? Give reasons.

Define the term ‘current sensitivity’ of a moving coil galvanometer.

The variation of inductive reactance (X_L) of an inductor with the frequency (f) of the ac source of 100 V and variable frequency is shown in fig.

1. Calculate the self-inductance of the inductor.
2. When this inductor is used in series with a capacitor of unknown value and a resistor of 10 Ω at 300 s^–1, maximum power dissipation occurs in the circuit. Calculate the capacitance of the capacitor.

Obtain the expression for capacitance for a parallel plate capacitor.

A galvanometer coil has a resistance of 12 Ω and the metre shows full scale deflection for a current of 3 mA. How will you convert the metre into a voltmeter of range 0 to 18 V?

A galvanometer coil has a resistance of 15 Ω and the metre shows full scale deflection for a current of 4 mA. How will you convert the metre into an ammeter of range 0 to 6 A?

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system ______.

The positive terminal of 12 V battery is connected to the ground. Then the negative terminal will be at ______.

1. Charge on each capacitor remains same and equals to the main charge supplied by the battery.
2. Potential difference and energy distribute in the reverse ratio of capacitance.
3. Effective capacitance is even les than the least of teh individual capacitances.

The work done in placing a charge of 8 × 10^–18 coulomb on a condenser of capacity 100 micro-farad is ______.