Physics - Online Test
Q1. The figure shows an unbalanced Wheatstone bridge. To balance the bridge:
Answer : Option B
Explaination / Solution:
To balance bridge
So X = 90
Q2. Damping is due to
Answer : Option B
Explaination / Solution:
Damping is proportional to the velocity of the mass through the medium , so it can be said that air drag ,friction offers damping.
Q3.
If we have two coherent sources vibrating in phase with same amplitude, then for an arbitrary point P with path difference corresponding to , the resultant intensity if the intensity due to each is I0 would be
Answer : Option C
Explaination / Solution:
No Explaination.
Q4.
if =magnetic intensity, =susceptibility, magnetic moment per unit volume equals
Answer : Option A
Explaination / Solution:
No Explaination.
Q5. The acceleration due to gravity at a depth d in terms of g the acceleration due to gravity at radius of the earth is
Answer : Option D
Explaination / Solution:
Acceleration due to gravity at the surface of the earth of radius RE
-(1)
Acceleration due to gravity at depth d from the surface of the earth
-(2)
From (1) & (2), we get
Q6. Diffusion in a p-n junction is due to
Answer : Option A
Explaination / Solution:
- In n-type semiconductor, the concentration of electrons is more compared to the concentration of holes. Similarly, in p-type semiconductor, the concentration of holes is more compared to the concentration of electrons
- The first process that occurs in the p-n semiconductor is diffusion
- In the formation of the p-n junction, due to the concentration gradient across the p and the n sides, the electrons diffuse from n region to p region and the holes diffuse from p region to n region.
Q7. If the position- time graph is a straight line
Answer : Option D
Explaination / Solution:
The principle is that the slope of the line on a position-time graph reveals useful information about the velocity of the object.
If the velocity is constant, then the slope is constant (i.e., a straight line).
Q8. Microwaves have a frequency of about
Answer : Option C
Explaination / Solution:
No Explaination.
Q9. If y(x, t) = a sin (kx + ωt + φ ) represents a wave function then ‘φ’ is
Answer : Option D
Explaination / Solution:
In the equation
y(x, t) = a sin (kx + t + )
The term represents initial phase or epoch
Hence the term is initial phase
Q10. Eddy Currents are
Answer : Option D
Explaination / Solution:
Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. By lenz's law an eddy current creates a magnetic field that opposes a change in the magnetic field that created it, and thus eddy currents react back on the source of the magnetic field.
