Solution of Chapter 17. Sample Question Paper-2 (Physics - Exemplar Book)

A capacitor of 4 μ F is connected in a circuit as shown. The internal resistance of the battery is 0.5 Ω. The amount of charge on the capacitor plates will be

Two charged particles traverse identical helical paths in a completely opposite sense in a uniform magnetic field .

A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increase or decrease? Explain.

Professor C.V Raman surprised his students by suspending freely a tiny light ball in a transparent vacuum chamber by shining a laser beam on it. Which property of EM waves was he exhibiting? Give one more example of this property.

A passenger in an aero plane shall

What is the shape of the wave front on earth for sunlight?

An electron (mass m) with an initial velocity is in an electric field . It’s de Broglie wavelength at time t is given by

Explain why elemental semiconductors cannot be used to make visible LED’s.

Five charges, q each are placed at the corners of a regular pentagon of side ‘a’ as shown.

(i) What will be the electric field at O if the charge from one of the corners (say A) is removed?

(ii) What will be the electric field at O if the charge q at A is replaced by –q?

Two cells of emf E₁ and E₂ have internal resistance r₁ and r₂. Deduce an expression for equivalent emf of their parallel combination.

Draw a circuit diagram of a potential divider using a cell and a rheostat. Also mark the output terminals.

If magnetic monopoles existed, how would the Gauss’s law of magnetism be modified?

From molecular viewpoint, discuss the temperature dependence of susceptibility for diamagnetism, Para magnetism and ferromagnetism.

A lamp is connected in series with a capacitor. Predict your observations for dc and ac connections. What happens in each case if the capacitance of the capacitor is reduced?

A plane electromagnetic wave of frequency 25 MHz travels in free space along the x-direction. At a particular point in space and time. . What is B at this point?

Define power of a lens. Show that it is inversely proportional to the focal length of the lens.

Two slits are made one millimetre apart and the screen is placed one metre away. What is the fringe separation when blue-green light of wavelength 500 nm is used?

A message signal of frequency 10 kHz and peak voltage of 10 volts is used to modulate a carrier of frequency 1 MHz and peak voltage of 20 volts. Determine (a) modulation index, and (b) the side bands produced.

Draw a circuit for determining internal resistance of a cell using a potentiometer. Explain the principle on which this method is based.

What do you mean by diamagnetism, paramagnetism and ferromagnetism?

For the same objective, find the ratio of the least separation between two points to be distinguished by a microscope for light of 5000 and electrons accelerated through 100V used as the illuminating substance.

Monochromatic light of frequency 6.0 × 10¹⁴ Hz is produced by a laser. The power emitted is 2.0 × 10^–3 W. (i) What is the energy of a photon in the light beam? (ii) How many photons per second, on an average, are emitted by the source?

State Bohr’s postulate for the ‘permitted orbits’ for electrons in a hydrogen atom. How this postulate was explained by de Broglie?

Explain a beta decay process with an example. Tritium has a half-life of 12.5y undergoing beta decay. What fraction of a sample of pure tritium will remain un-decayed after 25 y?

What is rectification? With the help of a labelled circuit diagram, explain full wave rectification using junction diode.

Explain briefly, with the help of a circuit diagram, how V-I characteristics of a p-n junction diode are obtained in (i) forward bias, and (ii) reverse bias. Draw the shapes of the curves obtained.

(i) Draw a block diagram of a communication system.

(ii) What is meant by ‘detection’ of amplitude modulated wave? Describe briefly the essential steps for detection.

Obtain an expression for potential energy of a system of two charges in an external field. A system consisting of two charges 7μ C and –2 μC are placed at (-9 cm, 0, 0) and (9 cm,0, 0) respectively in an external electric field E = A (1/r²) where A = 9 × 10⁵ C m². Calculate the potential energy of this system.

Define ‘mutual inductance’ of to coil. On what factors it depends? Two concentric circular coils, one of small radius r₁ and the other of large radius r₂, such that r₁ << r₂, are placed co-axially with centres coinciding. Obtain the mutual inductance of the arrangement.

Draw a ray diagram to show two refraction of light through a glass prism. Explain with help of a diagram the dependence of angle of deviation on the angle of incidence. Hence obtain the relation for the angle of minimum deviation in terms of angle of prism and refractive index of prism.