A. Amplifier
B. Generator
C. Loudspeaker
D. Microphone

A. A.C
B. D.C
C. Both of these
D. None

A. Alpha rays
B. Beta rays
C. Gamma rays
D. X-rays

A. Absence of water vapor in the Air
B. Clouds generate air currents and disturbances which do not promote frosty conditions
C. Clouds prevent radiation and therefore help the ground temperature remain higher
D. Moisture of air has been sucked away by the clouds.

A. Wavelength of noise
B. A musical instrument
C. A measure of sound level
D. All of these

A. Electromagnetism
B. Electroplating
C. Alchemy
D. Goldification

A. Thermometer
B. Hygrometer
C. Piezometer
D. Seismograph

A. inertia
B. Energy Conservation
C. Newton 3rd law
D. None of these

A. Concave
B. Convex
C. Combined Lens
D. None of these

A. Reflection
B. Refraction
C. Diffraction
D. Total Internal Reflection