XYZ Pre Assessment Sound and Light

What is the speed of sound in air?

• 1000 meters per second

• 500 meters per second

• 343 meters per second

• 123 meters per second

What is the unit of frequency?

• hertz

• megahertz

• gigahertz

• kilohertz

What is the phenomenon of bending of light when it passes from one medium to another?

• diffraction

• reflection

• refraction

• dispersion

What is the unit of power of a lens?

• volt

• watt

• meter

• dioptre

What is the process of reflection of sound waves from a surface called?

• diffraction

• absorption

• echo

• refraction

What is the unit of measurement of loudness of sound?

• hertz (Hz)

• watt (W)

• decibel (dB)

• ampere (A)

What is the angle of incidence equal to when light passes from one medium to another at the critical angle?

• The angle of incidence is equal to 90 degrees.

• The angle of incidence is equal to zero.

• The angle of incidence is equal to the angle of refraction.

• The angle of incidence is equal to the critical angle.

What is the unit of measurement of the wavelength of light?

• nanometer (nm)

• centimeter (cm)

• kilometer (km)

• meter (m)

What is the process of bending of light waves around obstacles called?

• diffraction

• reflection

• refraction

• absorption

What is the unit of measurement of the power of a light bulb?

• ampere

• ohm

• watt

• volt