A proton travels few distance in an electric field, then it enters a crossed magnetic field of 1 T and radius 0.2 m, find the velocity of proton
0.2 × 108 m s-1
0.2 × 107 m s-1
0.2 × 106 m s-1
2 × 107 m s-1
Two lens of focal lengths -20 cm and + 10 cm are put in combination, find the power of the combination
- 1 D
- 2 D
+ 5 D
+ 2 D
C.
+ 5 D
f1 = -20 cm
f2 = + 10 cm
Focal length of combination is
=
⇒ F = 20 cm
Power of combination
P =
=
P = + 5D
For a nuclear reactor to run in critical condition the reproduction factor k should be
= 1
> 1
< 1
>>> 1
A far sighted person has his near point 50 cm, find the power of lens he should use to see at 25 cm, clearly.
+ 1 D
+ 2 D
- 2 D
- 1 D
S32 absorbs energy and decays into which element after two -emissions?
Carbon
Aluminium
Oxygen
magnesium
Direction of electric field in P-N junction diode is
from P-side to N-side
From N-side to P-side
randomly oriented
electric field does not exist
Among the following which is used to control the rate of reaction of nuclear fissions reactions?
Water
Heavy water
Cadmium
Graphite
The series corresponding to minimum wavelength transition in H-atom
Balmer series
Lyman series
Paschen series
Brackett series
Assertion: When white light fall on the compact disc, multicolours are seen after reflection.
Reason: CD disc behaves like a prism.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: For nuclear reactor, it is desirable to have k = 1.
Reason: Sustained chain reaction occur at this critical condition.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.