Sound and Electricity

Name of the Student:

The frequency, which is audible to the human ear is

• 50 kHz
• 20 kHz
• 10000 kHz
• 15000 kHz

If a sound wave travels with a frequency of 1.25 x 10⁴ Hz at 344 m/s, the wavelength will be

• 27.52 m
• 275.2 m
• 0.02752 m
• 2.752 m

When a sound wave travels through air, the air particles _______________________

• vibrate along the direction of the wave motion
• vibrate perpendicular to the direction of the wave motion
• vibrate but not in any fixed direction
• do not vibrate

Velocity of sound in the atmosphere of a planet is 500 m/s. The minimum distance between the sources of sound and the obstacle to hear the echo, in point is

• 20 m
• 17 m
• 50 m
• 25 m

The rapid back and forth motion of a particle about its mean position is called (a)  

Kilowatt hour is the unit of

• Resistivity
• conductivity
• electrical energy
• electrical power

LED stands for

(a)  

MCB is used to protect house hold electrical appliances

• True
• False

Ohm's law states the relationship between power and voltage

• True
• False