821. A transistor is a semiconductor device with at least _____ terminals.
822. All electromagnetic radiations travel through vacuum with the speed
A. equal the speed of light
B. less than the speed of light
C. greater than the speed of light
D. (A) or (B)
823. The foot-pound is the unit of
824. In metals, the charge carriers are
D. none of these
825. A device that accelerates beams of charged particles is known as
826. The branch of Physics that deals with behaviour and properties of light is called
827. Which from the following is/are NOT electromagnetic radiation(s)?
I. Alpha rays
II. Beta rays
III. Gamma rays
A. I only
B. II only
C. III only
D. I and II
828. Which from the following electromagnetic radiation is associated with heat transfer through radiation?
B. Infrared rays
D. Gamma rays
829. The wire used to make the filament of a light bulb is made of
830. The wire used to make heating elements in electric kettles and irons are made of