Physics

What is factor affecting radius of gyration of a body?

A) Angular speed              B) Axis of rotation

C) Angular acceleration    D) Acceleration due to gravity

2. The length of a pendulum is increased by 21%. By what percentage of the period of the motion increases?

A) 9.8%        B) 10%    C) 11%      D) 21%

A cork rises from the bottom of the water and finally floats in water. Its graphical representation will be:

 If efficiency of petrol engine is \( \eta_1 \)and that of diesel engine is \( \eta_2 \) then, which of the following expression is correct?

A) \( \eta_1 = \eta_2 \)   B)\( \eta_1 > \eta_2 \)

C) \( \eta_1 < \eta_2 \)     D) \( \eta_1 \ge \eta_2 \)

 In which of the following thermodynamic process of the gas, work done is minimum?*

A) Isothermal    B) Adiabatic    C) Isobaric    D) Isochoric

 What is the distance between node and antinode in a stationary wave in terms of wavelength?

A) \( \frac{\lambda}{2} \)    B) \( \frac{\lambda}{4} \)     C) \( \lambda \)     D) \( 2\lambda \)

 Time taken by light to cross a glass slab of thickness 5cm and refractive index of 1.5 will be:

A) 0.2 ns   B) 0.25 ns     C) 0.3 ns     D) 0.35 ns

Which portion of the given figure represents the coercivity?                                    

A) CD    B) AD    C) AG     D) AE

 A coil has a resistance of\( 8\Omega \)and an inductive reactance \( 6\Omega \). What will be the impedance?

A) \( 6\Omega \)   B) \( 8\Omega \)  C) \( 10\Omega \)   D) \( 14\Omega \)

.A diode as a rectifier converts

A) varying dc into constant dc

B) dc into ac

C) high voltage into low voltage

D) ac into dc

a) The angular velocity of the earth around the sun increases when it comes closure to the sun, why? 

b) A disc having moment of inertia \( 10\text{ kg m}^2 \) about its center rotates steadily with angular velocity of \( 20\text{ rad s}^{-1} \). Find: 

i) Rotational kinetic energy

ii) Number of revolution per second

a) State Stoke's law and use it to derive an expression for the determination coefficient of viscosity of given liquid. 

b) Write equation of continuity. Also write its two applications.

OR 

a) Define simple harmonic motion. Write general equations for displacement and acceleration in simple harmonic motion. 

 b) Plot a graph of velocity of a particle in SHM. 

c) What will be the time period of simple pendulum at the centre of the earth? Justify. 

a) Apply first law of thermodynamics to obtain the relation \( C_p - C_v = R \), where symbols have their usual meanings. 

 b) A petrol engine consumes \( 10\text{kg} \) of petrol in one hour. The calorific value of petrol is \( 1.14 \times 10^4\text{ calg}^{-1} \). The power of the engine is \( 30\text{kW} \). Calculate the efficiency of the engine. 

a) Obtain Laplace's formula for velocity of sound in air starting from Newton's formula. 

 b) A car producing note of frequency \( 500\text{Hz} \) approaches and passes a stationary observer at the steady speed of \( 20\text{ms}^{-1} \). Calculate change of frequency heard by the observer (Velocity of sound = \( 340\text{ms}^{-1} \)). 

a) Analyze the given graph and name the type of material represented by graph A and graph B. 

b) Define potential gradient. A potentiometer wire is\( 10\text{m} \) long. It has a resistance of \( 20\Omega \). It is connected in series with a battery of \( 3\text{V} \) and a resistance of \( 10\Omega \). Calculate the potential gradient along the wire. 

a) State and explain Lenz's law. 

b) A bar magnet falls through a metal ring, will its acceleration be equal to g? Justify your answer. 

c) According to Faraday's law of electromagnetic induction, induced \( \text{emf} = -N\frac{d\phi}{dt} \) What does the negative sign indicate? 

OR 

a) Define rms value of current. 

b) The emf in an ac circuit is represented as \( E = E_0 \sin \omega t \). Show that voltage through an inductor leads current by \( \frac{\pi}{2} \). Also draw a phasor diagram. 

c) Why does a capacitor block d.c.? 

a) Define half and mean life. 

 b) Calculate the value of half life and decay constant from fig (a). 

 c) Which one curve in fig (b) has more value of decay constant? Justify.

a) Draw free body diagram of oil drop falling through air in Millikan's oil drop experiment for both cases; when field is given and when field is absent. What is the conclusion of this experiment? 

b) How do P and S waves differ? 

a) Thin films such as soap bubbles show beautiful colors when illuminated by white light. Why? 
b) "The bright and dark fringes are equally spaced". Justify this statement from Young's double slits experiment. 
c) A diffraction grating has 400 lines per mm and is illuminated normally by monochromatic light of wavelength 600nm. Calculate
i) The grating spacing.
ii) The angle to the normal at which the first order maximum is seen.
iii) The numbers of diffraction maxima obtained. 

OR
a) Why is an end correction necessary for organ pipes? 

b) How is it possible to estimate that the vessel kept under an open tap of water is about to fill? Justify. 

c) In case of an organ pipe, notes of frequencies 200Hz, 600Hz and 1000Hz are heard. Is the pipe open or closed? 

d) Describe the various modes of vibration of the air column in a closed organ pipe. 

a) What are excitation potential and ionization potential? 

b) Given figure shows the different energy levels of a hydrogen atom. Estimate the energy values for n=4 and 5. How many different transitions are possible? 

c) What is rectifier? Describe the working of full wave rectifier using two P-N junction diodes.

a) What is photo electric effect? 

b) Describe Einstein's photoelectric equation 

c) State and explain Bragg's law of X-ray diffraction 

d) Calculate the value of Planck's constant and work function from the given figure. 

a) A circular coil of radius R is carrying a constant current I. Find an expression for magnetic field at point P, which is at a distance x on its axial line. 

b) Why is Hall voltage much more measurable in semiconductors than metals? Explain. 

c) Draw magnetic field lines around the two parallel current carrying conductors in which currents are in opposite direction. 

d) Two long parallel conductors are placed 0.1 m apart and carry currents of 3 A and 2 A, respectively in the same direction. Calculate the force per unit length experienced by each conductor due to the other. (\( \mu_0 = 4\pi \times 10^{-7}\text{Hm}^{-1} \))