The frequency of electromagnetic wave, which is best suited to observe a particle of radius 3 × 10-4 cm, is of the order of
1015
1014
1013
1012
Which of the following has minimum wavelength?
X-rays
Ultraviolet rays
y-rays
Cosmic rays
Ozone layer blocks the radiations of wave length
less than 3 × 10-7 m
equal to 3 × 10-7 m
more than 3 × 10-7 m
all of the above
In a certain region of space electric file and magnetic field are perpendicular to each other and an electron enters in region perpendicular to the direction of and both and moves undeflected, then velocity of electron is
Which of the following rays are not electromagnetic waves?
β-rays
Heat rays
What is the cause of "Green house effect"?
Infrared rays
Radio-waves
The structure of solids is investigated by using
cosmic rays
infrared radiations
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of
sky wave
sea wave
both (a) and (b)
The charging current for a capacitor at any instant is 0.25 A.The displacement current across the capacitor plates at that instant is
0.5 A
0.25 A
2.5 A
1 A
Which one of the following electromagnetic radiations have the smallest wavelength?
Ultraviolet waves
Microwaves
