Physics Test

Question 1
4 / -1

Directions: From the statements of Assertion and Reason mark the correct answer from the options.

(a) If both assertion and reason are true, and reason is the correct explanation of assertion.

(b) If both assertion and reason are true, but reason is not the correct explanation of assertion.

(c) If assertion is true, but reason is false.

(d) If both assertion and reason are false.

Assertion: Diamagnetic materials can exhibit magnetism.

Reason: Diamagnetic materials have permanent magnetic dipole moment.

A
(a)

B
(b)

C
(c)

D
(d)

Question 2
4 / -1

For a certain radioactive substance, it is observed that after 4 hours, only 6.25% of the original sample is left undecayed. Which of the following statements is incorrect?

A
The half life of the sample is 1 hr.

B
The mean life of the sample is 1/2 hr.

C
The decay constant of the sample is (ln 2) hr^-1.

D
After further 4 hours, the amount of the substance leftover would be only 0.39% of the original amount.

Question 3
4 / -1

A police car horn emits sound at a frequency of 240 Hz when the car is at rest. If the speed of sound is 330 m/s, the frequency heard by an observer who is approaching the car at a speed of 11 m/s, is

A
248 Hz

B
244 Hz

C
240 Hz

D
230 Hz

Question 4
4 / -1

The magnetic susceptibility of a material of a rod is 449. Permeability of vacuum is 4π x 10^-7henry/metre. The absolute permeability of the material of the rod (in henry/metre) is

A
π x 10^-4

B
2π x 10^-4

C
3π x 10^-4

D
4π x 10^-4

Question 5
4 / -1

A Carnot engine works as a refrigerator between 250 K and 300 K. If it receives 750 calories of heat from the reservoir at the lower temperature, then the amount of heat rejected at the higher temperature is

A
900 cal

B
625 cal

C
750 cal

D
1000 cal

Question 6
4 / -1

The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV and the stopping potential for a radiation incident on this surface is 5 V. The incident radiation lies in

A
ultraviolet region

B
infrared region

C
visible region

D
X-ray region

Question 7
4 / -1

A long horizontal rod has a bead, which can slide along its length and is initially placed at a distance L from one end A of the rod. The rod is set in angular motion about A with constant angular acceleration α . If the coefficient of friction between the rod and the bead is and gravity is neglected, then the time after which the bead starts slipping is

A
\(\sqrt{\frac{\mu}{\alpha}}\)

B
\(\frac{\mu}{\sqrt{\alpha}}\)

C
\(\frac{1}{\sqrt{\mu \alpha}}\)

D
infinitesimal

Question 8
4 / -1

Directions: The following question contains 4 choices (A), (B), (C) and (D), out of which ONLY ONE is correct

In the experiment to determine the speed of sound using a resonance column,

A
prongs of the tuning fork are kept in a vertical plane

B
prongs of the tuning fork are kept in a horizontal plane

C
in one of the two resonances observed, the length of the resonating air column is close to the wavelength of sound in air

D
in one of the two resonance observed, the length of the resonating air column is close to half of the wavelength of sound in air

Question 9
4 / -1

The figure shows variation of photocurrent with anode potential for a photosensitive surface for three different radiations. Let I_a, I_band I_cbe the intensities and v_a, v_band v_cbe the frequencies for the curves a, b and c, respectively. Then,

A
\(\nu_{a}=\nu_{b}\) and \(I_{a} \neq I_{b}\)

B
\(v_{a}=v_{c}\) and \(I_{a}=I_{b}\)

C
\(v_{a}=v_{b}\) and \(I_{a}=I_{b}\)

D
\(v_{b}=v_{c}\) and \(I_{b} \neq I_{c}\)

Question 10
4 / -1

The bob of a simple pendulum is a spherical hollow ball filled with water. A plugged hole near the bottom of the oscillating bob gets suddenly unplugged. During observation, till water is coming out, the time period of oscillation would

A
first increase and then decrease to the original value

B
first decrease and then increase to the original value

C
remain unchanged

D
increase towards a saturation value

Submit Test

Physics Test - ...

Question 1

(a)

(b)

(c)

(d)

Question 2

The half life of the sample is 1 hr.

The mean life of the sample is 1/2 hr.

The decay constant of the sample is (ln 2) hr-1.

After further 4 hours, the amount of the substance leftover would be only 0.39% of the original amount.

Question 3

248 Hz

244 Hz

240 Hz

230 Hz

Question 4

π x 10-4

2π x 10-4

3π x 10-4

4π x 10-4

Question 5

900 cal

625 cal

750 cal

1000 cal

Question 6

ultraviolet region

infrared region

visible region

X-ray region

Question 7

\(\sqrt{\frac{\mu}{\alpha}}\)

\(\frac{\mu}{\sqrt{\alpha}}\)

\(\frac{1}{\sqrt{\mu \alpha}}\)

infinitesimal

Question 8

prongs of the tuning fork are kept in a vertical plane

prongs of the tuning fork are kept in a horizontal plane

in one of the two resonances observed, the length of the resonating air column is close to the wavelength of sound in air

in one of the two resonance observed, the length of the resonating air column is close to half of the wavelength of sound in air

Question 9

\(\nu_{a}=\nu_{b}\) and \(I_{a} \neq I_{b}\)

\(v_{a}=v_{c}\) and \(I_{a}=I_{b}\)

\(v_{a}=v_{b}\) and \(I_{a}=I_{b}\)

\(v_{b}=v_{c}\) and \(I_{b} \neq I_{c}\)

Question 10

first increase and then decrease to the original value

first decrease and then increase to the original value

remain unchanged

increase towards a saturation value

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Question Analysis

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The decay constant of the sample is (ln 2) hr^-1.

π x 10^-4

2π x 10^-4

3π x 10^-4

4π x 10^-4