Physics - Online Test
Q1. The flux linked with a coil
at any instant t is given by ΦB = 10t 2 − 50t + 250. The induced emf at t = 3s is
Answer : Option B
Explaination / Solution:
Q2. The blue print for making ultra durable synthetic material is mimicked from
Answer : Option C
Explaination / Solution:
No Explaination.
Q3. Which of the following
electromagnetic radiation is used for viewing objects through fog
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. For light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is,
Answer : Option A
Explaination / Solution:
n= 2;
i=90◦
n = sin i / sin r
sin
r = sin i / n
= sin 90◦/2 = ½
r
= sin-1(1/2) = 30◦
Q5. Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are
Answer : Option C
Explaination / Solution:
Imax
= I1 + I2 + 2√(I1I2)
=
I + 4I + 2√(4I2)
=
I + 4I + 4I = 9I
Imin
= I1 + I2 - 2√(I1I2)
=
I + 4I − 2√(4I2)
=
I + 4I − 4I = I
Q6. An electric dipole is
placed at an alignment angle of 30º with an electric field of 2 × 105
N C-1. It experiences a torque equal to 8 N m. The charge on the
dipole if the dipole length is 1 cm is
Answer : Option B
Explaination / Solution:
Q7. When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is V/4. The threshold wavelength for the metallic surface is
Answer : Option D
Explaination / Solution:
Q8. A carbon resistor of (47 ± 4.7 ) k Ω to be marked with rings of different colours for its identification. The colour code sequence will be
Answer : Option B
Explaination / Solution:
Q9. The ratio between the first three orbits of hydrogen atom is
Answer : Option C
Explaination / Solution:
The
radius of the nth orbit is rn
= n2r0
rn ∝ n2
r1:r2:r3 = 1:4:9
Q10. A circular coil of radius 5
cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of
the coil is
Answer : Option B
Explaination / Solution:
