Physics - Online Test
Q1. An electric field 
exists in a certain region
of space. Then the potential difference V = Vo – VA,
where Vo is the potential at the origin and VA is the
potential at x = 2 m is:
exists in a certain region
of space. Then the potential difference V = Vo – VA,
where Vo is the potential at the origin and VA is the
potential at x = 2 m is:
Answer : Option B
Explaination / Solution:
Q2. A light source of wavelength 520 nm emits 1.04 ×
1015 photons per second while the second source of 460 nm produces 1.38 × 1015 photons per
second. Then the ratio of power of second source to that of first source is
Answer : Option C
Explaination / Solution:
Q3. In a large building, there
are 15 bulbs of 40W, 5 bulbs of 100W, 5 fans of 80W and 1 heater of 1kW are
connected. The voltage of electric mains is 220V. The minimum capacity
of the main fuse of the building will be
Answer : Option D
Explaination / Solution:
Q4. If the nuclear radius of 27Al is 3.6 fermi,
the approximate nuclear radius of 64Cu is
Answer : Option C
Explaination / Solution:
Q5. A bar magnet of length l
and magnetic moment M is bent in the form of an arc as shown in figure. The new
magnetic dipole moment will be
Answer : Option B
Explaination / Solution:
Q6. The barrier potential of a p-n junction depends on (i) type of semiconductor material (ii) amount of doping (iii) temperature. Which one of the following is correct?
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. In an electrical circuit, R,
L, C and AC voltage source are all connected in series. When L is
removed from the circuit, the phase difference between the voltage and current
in the circuit is π /3 . Instead, if C is removed from the circuit,
the phase difference is again π / 3 . The power factor of the circuit is
Answer : Option C
Explaination / Solution:
Q8. The particle which gives mass to protons and neutrons are
Answer : Option A
Explaination / Solution:
No Explaination.
Q9. If the magnetic monopole exists, then which of the Maxwell’s equation to be modified?.
Answer : Option B
Explaination / Solution:
No Explaination.
Q10. A ray of light travelling
in a transparent medium of refractive index n falls, on a surface separating
the medium from air at an angle of incidents of 45º. The ray can undergo total
internal reflection for the following n,
Answer : Option D
Explaination / Solution:
For
total internal reflection
i > C;
sin
i > sin C;
sin
45◦ > 1/n
1/√2
> 1/n
n>√2
n>1.414
Here, n=1.5
