The phenomenon in which electrons are ejected from metal surfaces when electromagnetic waves fall on them is called
Photoelectric effect
Magnetism
Spectrum
Interference
The pitch of a note depends on
The frequency of the sound
The wavelength of the sound
Speed of a sound
All the above
A ship can determine the depth of a shoal of fish or the sea-bed with the help of
A sonar
Radio waves
Micro waves
X-rays
The longitudinal and transverse waves produced by earthquake are called
Infrared waves
Ultrasonic waves
Seismic waves
The distance between two successive crest or trough is called
Displacement
Wavelength
Frequency
Amplitude
The spreading of wave at the edges or obstacle is called
Reflection
Refraction
Diffraction
Which technique is used by bats to judge how far an object is?
Ultrasonic echo technique
X - ray technique
Infrasonic echo technique
Ultraviolet radiation technique
Which rays are used to kill cancer cells and also harmful bacteria in food and surgical instruments?
UV - radiation
Ultraviolet radiation
Gama rays
If the earthquake occur under the sea, the seismic energy can be transmitted to the water and produce
Ultrasonic echo
Ultra violet radiation
Tsunami
Waves travel more slowly in
Ocean
River water
Shallow water
Deep water
