A T V tube requires an accelerating voltage of the order of
150 V
1000 V
20 kV
500 kV
Who discovered radioactivity?
Albert Einstein
Ernest Rutherford
Antoine Henri Becquerel
James Chadwick
A certain nucleus A (mass number 238 and atomic number 92) is radioactive and becomes a nucleus B (mass number 234 and atomic number 90) by the loss of a particle. What particle was emitted?
Gamma
neutrino
alpha
beta
The atoms of different elements which have same mass number A, but differ in their atomic number Z are called
Isotopes
Isobars
Isotones
Nucleons
The screen of a cathode ray tube cannot be coated with:
zinc sulphide
zinc platinocyanide
zinc silicate with manganese traces
barium platinocyanide
The maximum number of electrons that the first shell can accomodate
2
4
8
18
Why is graphite coating made on the inner side of the cathode ray tube ?
To change the brightness pattern on screen
To avoid the effect of external electric field on the beam of electrons
To avoid collisions of electrons with the air molecules
To produce fluorescence on the screen
The electron emitter must have
low work function and low melting point
high work function and high melting point
high work function and low melting point
low work function and high melting point
The atoms having different number of protons and different number of electrons but same number of neutrons are called
None of these
The difference between the expected and actual mass of an alpha particle is 0.02928 u. How much is the binding energy per nucleon for alpha particles ?
5 MeV
7.5 MeV
9.8 MeV
6.81 MeV
