Production of heat due to an electric current flowing through a conductor is given by _________________?

A. Joule effect
B. Joule thomsons effect
C. Comptons effect
D. Feed back effect

Three equal resistors connected in series with a source of e m f together dissipate 10 W of power each. What will be the power dissipated if the same resistors are connected in parallel across the same source of e m f ?

A. 40 w
B. 90w
C. 100w
D. 120w

Thermocouples convert___________________?

A. Heat energy into electrical energy
B. Heat energy into light energy
C. Heat energy into mechanical energy
D. Mechanical energy into heat energy

The periodic alternation of sound between maximum and minimum loudness are called___________________?

A. Silence zone
B. Interference
C. Beats
D. Resonance

Beats are the results of____________________?

A. Diffraction of sound waves
B. Constructive and destructive interference
C. Polarization
D. Destructive interference

Doppler effect applies to____________________?

A. Sound wave only
B. Light wave only
C. Both sound and light waves
D. Neither sound nor light wave

A simple pendulum has a bob of mass m and its frequency is f. If we replaced the bob with a heavier one say of 2m then that will be its new frequency ?

A. 1/4f
B. 1/2f
C. Frequency lower than 20 hz
D. 2f

In open organ pipe___________________?

A. Only even harmonics are present
B. Only odd harmonics are present
C. Both even and odd harmonics are present
D. Selected harmonics are present

The dimension of elastic modulus is ___________________ ?

A. Ml-1t-2
B. Ml-2t-2
C. Mlt-2
D. Ml2t-2

Waves produced at the surface of water by a pencil executing vibrating motion if held vertically at a frequency of 50Hz are__________________?

A. Longitudinal
B. Transverse
C. Periodic
D. Both a and c