Two capacitors when connected in series have a capacitance of 3 μF,and when connected in parallel have a capacitance of 16 μF.Their individual capacities are

1 μF,2 μF
6 μF,2 μF
12 μF,4 μF
3 μF,16 μF

Solution

A man wants to see two poles, separately, situated at 11 km.The minimum distance (approximately) between these poles will be

5 m
0.5 m
1 m
3 m

If ε₀ and μ₀ are the electric permittivity and magnetic permeability in vacuum, e and mare corresponding quantities in medium, then refractive index of the medium is

\(\sqrt{\frac{\varepsilon }{\varepsilon _{0}}}\)
\(\sqrt{\frac{\varepsilon_{0} \mu }{\varepsilon \mu _{0}}}\)
\(\sqrt{\frac{\varepsilon_{0} \mu_{0} }{\varepsilon \mu }}\)
\(\sqrt{\frac{\varepsilon \mu }{\varepsilon_{0} \mu_{0}}}\)

Solution

In a bridge rectifier, the number of diodes required is

If \(\overrightarrow{E}\) and \(\overrightarrow{B}\) represent electric and magnetic field vectors of the electromagnetic waves, then the direction of propagation of the waves will be along

\(\overrightarrow{B}\) × \(\overrightarrow{E}\)
\(\overrightarrow{E}\)
\(\overrightarrow{B}\)
\(\overrightarrow{E}\) × \(\overrightarrow{B}\)

Solution

A circular loop of area 0.02 m² carrying a current of 10A, is held with its plane perpendicular to a magnetic field induction 0.2 T. The torque acting on the loop is

0.01 Nm
0.001 Nm
zero
0.8 Nm

Solution

Torque on loop τ = nIAB cos θ; Here θ= 90º

∴ τ = 0.

A person carrying a whistle emitting continuously a note of 272 Hz is running towards a reflecting surface with a speed of 18 km h^–1. The speed of sound in air is 345 m s^–1.The number of beats heard by him is

4
6
8
zero

Solution

DIRECTIONS: Each question contains STATEMENT-1 and STATEMENT-2. Choose the correct answer(ONLY ONE option is correct ) from the following

Statement 1 :Energy cannot be divided by volume.

Statement 2 :Because dimensions for energy and volume are different

(a) Statement -1is false, Statement-2 is true
(b) Statement -1 is true, Statement-2 is true; Statement -2 is a correct explanation for Statement-1
(c) Statement -1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1
(d)Statement -1is true, Statement-2 is false

Solution

(a) Statement -1is false, Statement-2 is true

In a thermocouple,the temperature of the cold junction and the neutral temperature are –40°C and 275° Crespectively. If the cold junction temperature is increased by60°C, the neutral temperature and temperature of in version respectively become

275°C, 530°C
355°C, 530°C
375°C, 590°C
355°C, 590°C

Solution

When the temperature of cold junction is increased,the neutral temperature remains constant for a given thermocouple and it is independent of the temperature of the cold junction.

∴ θ_n= 275°C, θ_i– θ_n= θ_n– θ_c

∴ θ_i= 2θ_n– θ_c= 530°C.

If an electron and positron annihilate, then the energy released is

3.2 × 10^-13 J
1.6 × 10^-13 J
4.8 × 10^-13 J
6.4 × 10^-13 J

Solution

Which of the following formula is wrong?

\(C_{v}=\frac{R}{\gamma -1}\)
\(C_{p}=\frac{\gamma R}{\gamma -1}\)
C_p/C_v = γ
C_p - C_v = 2R

Solution

The difference of C_p and C_v is equal to R, not 2R

A gamma ray photon creates an electron-positron pair. If the rest mass energy of an electron is 0.5 MeV and the total kinetic energy of the electron-positron pair is 0.78 MeV,then the energy of the gamma ray photon must be

0.78 MeV
1.78 MeV
1.28 MeV
0.28 MeV

Solution

Energy of γ-ray photon = Rest mass energy + K.E.= 2 (0.5) + 0.78 = 1.78 MeV

A cylinder is filled with non-viscous liquid of density d to a height h₀ and a hole is made at a height h₁from the bottom of the cylinder. The velocity of the liquid is suing out of the hole is

\(\sqrt{2gh_{0}}\)
\(\sqrt{2gh_{0}}\)
\(\sqrt{2g(h_{1})}\)
\(\sqrt{2g(h_{1})}\)

Solution

Velocity of liquid flowing out of hole =\(\sqrt{2gh}\)
Here h = (h₀– h₁)

Which of the following is not the case with the image formed by a concave lens?

It may be erect or inverted
It may be magnified or diminished
It may be real orvirtual
Real image may be between the pole and focus or beyond focus

In the circuit shown below, if the resistance of voltmeter is 4 kΩ, then the error in the reading of voltmeter will be

50%
68%
17%
33.3%

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