HSC Science (Electronics) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions for Physics

Compare the rates of emission of heat by a blackbody maintained at 627°C and at 127°C, if the black bodies are surrounded by an enclosure at 27°C. What would be the ratio of their rates of loss of heat? 

What are beats?

State any four applications of beats.

Explain the production of beats and deduce analytically the expression for beats frequency.

State the conditions when the magnetic potential energy of a magnetic dipole (current-carrying coil) kept in the uniform magnetic field be minimum and maximum. 

The role of inductance is equivalent to ______ 

A plane of a coil of 10 turns is tightly wound around a solenoid of diameter 2 cm having 400 turns per centimeter. The relative permeability of the core is 800. Calculate the inductance of the solenoid. 

Prove that the frequency of beats is equal to the difference between the frequencies of the two sound notes giving rise to beats.

What is the average value of alternating current over a complete cycle?

Two tuning forks of frequencies 320 Hz and 340 Hz are sounded together to produce a sound wave. The velocity of sound in air is 326.4 m/s. Calculate the difference in wavelengths of these waves.

A ceiling fan has a moment of inertia of 2 kg. m². It attains maximum frequency of 60 r.p.m. in 2π seconds. Calculate its power rating.

If beat frequency is 2 Hz, what is the time interval between success waxings?

Draw a neat labelled P - V diagram for a typical heat engine. 

The thermal efficiency of a heat engine is 25%. If in one cycle the heat absorbed from the hot reservoir is 50000 J, what is the heat rejected to the cold reservoir in one cycle?

What are the steps through which a refrigerant goes in one complete cycle of refrigeration?

A sonometer wire under a tension of 40 N vibrates in unison with a tuning fork of frequency 384 Hz. Find the beat frequency when the tension in the wire is reduced by 0.21 N.

A blackbody at 327 °C, when suspended in a black enclosure at 27 °C, loses heat at a certain rate. Find the temperature of the body at which its rate of loss of heat by radiation will be half of the above rate. Assume that the other conditions remain unchanged. 

What does a heat engine consist of?

A short bar magnet of moment 0.5.A m² is suspended in a horizontal magnetic field of 1000 gauss such that it can rotate freely in a horizontal plane. Calculate (i) the magnitude of the torque and (ii) the magnetic potential energy when its angular displacement with respect to the direction of the field is 10°.

The power factor of LCR circuit is ______.