Amplitude modulation has
one carrier with infinite frequencies
one carrier with two side band frequencies
one carrier with high frequency
one carrier
An LED is constructed from a p-n junction based on a certain semi-conducting material whose energy gap is 1.9 eV. Then, the wavelength of the emitted light is
6.5 × 10-7 m
2.9 × 10-9 m
9.1 × 10-5 m
1.6 × 10-8 m
The waves used for Line-of-Sight (LOS) communication is
sound waves
ground waves
sky waves
space waves
D.
space waves
The space waves are the radio waves of very high frequency (30 MHz to 300 MHz), ultra high frequency (300 MHz to 3000 MHz) arid microwave (more than 3000 MHz). Thus, space wave propagation cari be utilised for transmitting high frequency TV arid FM signals.
The input characteristics of a transistor in CE mode is the graph obtained by plotting
IB against IC at constant VCE
IB against VBE at constant VCE
IB against IC at constant VBE
IB against VCE at constant VBE
In a Young's double slit experiment, the slit separation is 0.5 mm and the screen is 0.5 m from the slits. For a monochromatic light of wavelength 500 nm, the distance of 3rd maxima from 2nd minima on the other side of central maxima is
22.5 mm
2.75 mm
2.25 mm
2.5 mm
Calculate the focal length of a reading glass of a person if the distance of distinct vision is 75 cm.
75.2 cm
25.6 cm
100.4 cm
37.5 cm
A person wants a real image of his own, 3 times enlarged. Where should he stand infront of a concave mirror of radius of curvature of 30 cm ?
− 90 cm
− 10 cm
− 20 cm
− 30 cm
If ε0 and µ0 are the permittivity and permeability of free space and ε and μ are the corresponding quantities for a medium. Then, refractive index of the medium is
1
insufficient information