QBManager

TEST SERIES (PHYSICS FST)

266469 Assertion: Young's modulus for a perfectly plastic body is zero. Reason: For a perfectly plastic body, restoring force is zero.

1 Assertion is correct, reason is correct; reason is a correct explanation for assertion.

2 Assertion is correct, reason is correct; reason is not a correct explanation for assertion.

3 Assertion is correct, reason is incorrect.

4 Assertion is incorrect, reason is incorrect.

Explanation:

a
Young's modulus of a material
$Y = \frac{Stress}{Strain}$
Here, Stress $= \frac{Restoring force}{Area}$
As restoring force is zero.
$∴ Y = 0$

**NCERT-XI-II-170**

TEST SERIES (PHYSICS FST)

266470 A 120 m long train is moving towards west with a speed of 10 ms . A bird flying east with a speed of $5 m / s$ crosses the train. The time taken by the bird to cross the train will be

1 16 sec

2 12 sec

3 10 sec

4 8 sec

Explanation:

d
Relative velocity $= 10 + 5 = 15 m / s$
Time taken by the bird to cross the train
$= \frac{120}{15} = 8 \sec .$

**NCERT-XI-I-14**

TEST SERIES (PHYSICS FST)

266472 Energy of photon whose frequency is $10^{12} MHz$ , will be

1

4.14 \times 10^{3} KeV

2

4.14 \times 10^{2} KeV

3

4.14 \times 10^{3} MeV

4

4.14 \times 10^{3} eV

Explanation:

d
$\begin{aligned} E (eV) & = \frac{hv}{e} = \frac{6.6 \times 10^{- 24} \times 10^{12} \times 10^{6}}{1.6 \times 10^{- 19}} \\ = 4.14 \times 10^{3} eV \end{aligned}$

**NCERT-XII-II-283**

TEST SERIES (PHYSICS FST)

266473 Astep-down transformer is used on a 1000 V line to delinear 20 A at 120 V at the secondary coil. If the efficiency of the transformer is $80 %$ the current drawn from the line is

1 3 A

2 30 A

3 0.3 A

4 2.4 A

Explanation:

a
$\begin{aligned} η & = \frac{Output}{Input} \Rightarrow \frac{80}{100} = \frac{20 \times 20}{1000 \times i_{1}} \\ \Rightarrow i_{1} & = \frac{20 \times 120 \times 100}{1000 \times 80} \\ i_{1} & = 3 A \end{aligned}$

**NCERT-XII-I-139**

TEST SERIES (PHYSICS FST)

266474 A uniform electric field $E$ exists along positive x -axis. The work done in moving a charge 0.5 C through a distance 2 m along a direction making an angle $60^{\circ}$ with x -axis is 10 J . Then the magnitude of electric field is :

1

5 V^{- 1}

2

2 V m^{- 1}

3

\sqrt{5} v^{- 1}

4

20 {Vm}^{- 1}

Explanation:

d
Force acting on the charged particle due to electric fiel $d = q E$
Work done in moving through distance S,
$\begin{aligned} W & = q \vec{E} . S \\ = (q E) \times (S) \times (\cos θ) \\ ∴ 10 J & = (0.5) \times E \times 2 \cos 60^{\circ} \\ E & = 10 \times 2 = 20 {NC}^{- 1} \\ = 20 {Vm}^{- 1} \end{aligned}$

**NCERT-XII-I-14**

TEST SERIES (PHYSICS FST)

266469 Assertion: Young's modulus for a perfectly plastic body is zero. Reason: For a perfectly plastic body, restoring force is zero.

1 Assertion is correct, reason is correct; reason is a correct explanation for assertion.

2 Assertion is correct, reason is correct; reason is not a correct explanation for assertion.

3 Assertion is correct, reason is incorrect.

4 Assertion is incorrect, reason is incorrect.

Explanation:

a
Young's modulus of a material
$Y = \frac{Stress}{Strain}$
Here, Stress $= \frac{Restoring force}{Area}$
As restoring force is zero.
$∴ Y = 0$

**NCERT-XI-II-170**

TEST SERIES (PHYSICS FST)

266470 A 120 m long train is moving towards west with a speed of 10 ms . A bird flying east with a speed of $5 m / s$ crosses the train. The time taken by the bird to cross the train will be

1 16 sec

2 12 sec

3 10 sec

4 8 sec

Explanation:

d
Relative velocity $= 10 + 5 = 15 m / s$
Time taken by the bird to cross the train
$= \frac{120}{15} = 8 \sec .$

**NCERT-XI-I-14**

TEST SERIES (PHYSICS FST)

266472 Energy of photon whose frequency is $10^{12} MHz$ , will be

1

4.14 \times 10^{3} KeV

2

4.14 \times 10^{2} KeV

3

4.14 \times 10^{3} MeV

4

4.14 \times 10^{3} eV

Explanation:

d
$\begin{aligned} E (eV) & = \frac{hv}{e} = \frac{6.6 \times 10^{- 24} \times 10^{12} \times 10^{6}}{1.6 \times 10^{- 19}} \\ = 4.14 \times 10^{3} eV \end{aligned}$

**NCERT-XII-II-283**

TEST SERIES (PHYSICS FST)

266473 Astep-down transformer is used on a 1000 V line to delinear 20 A at 120 V at the secondary coil. If the efficiency of the transformer is $80 %$ the current drawn from the line is

1 3 A

2 30 A

3 0.3 A

4 2.4 A

Explanation:

a
$\begin{aligned} η & = \frac{Output}{Input} \Rightarrow \frac{80}{100} = \frac{20 \times 20}{1000 \times i_{1}} \\ \Rightarrow i_{1} & = \frac{20 \times 120 \times 100}{1000 \times 80} \\ i_{1} & = 3 A \end{aligned}$

**NCERT-XII-I-139**

TEST SERIES (PHYSICS FST)

266474 A uniform electric field $E$ exists along positive x -axis. The work done in moving a charge 0.5 C through a distance 2 m along a direction making an angle $60^{\circ}$ with x -axis is 10 J . Then the magnitude of electric field is :

1

5 V^{- 1}

2

2 V m^{- 1}

3

\sqrt{5} v^{- 1}

4

20 {Vm}^{- 1}

Explanation:

d
Force acting on the charged particle due to electric fiel $d = q E$
Work done in moving through distance S,
$\begin{aligned} W & = q \vec{E} . S \\ = (q E) \times (S) \times (\cos θ) \\ ∴ 10 J & = (0.5) \times E \times 2 \cos 60^{\circ} \\ E & = 10 \times 2 = 20 {NC}^{- 1} \\ = 20 {Vm}^{- 1} \end{aligned}$

**NCERT-XII-I-14**

TEST SERIES (PHYSICS FST)

266469 Assertion: Young's modulus for a perfectly plastic body is zero. Reason: For a perfectly plastic body, restoring force is zero.

1 Assertion is correct, reason is correct; reason is a correct explanation for assertion.

2 Assertion is correct, reason is correct; reason is not a correct explanation for assertion.

3 Assertion is correct, reason is incorrect.

4 Assertion is incorrect, reason is incorrect.

Explanation:

a
Young's modulus of a material
$Y = \frac{Stress}{Strain}$
Here, Stress $= \frac{Restoring force}{Area}$
As restoring force is zero.
$∴ Y = 0$

**NCERT-XI-II-170**

TEST SERIES (PHYSICS FST)

266470 A 120 m long train is moving towards west with a speed of 10 ms . A bird flying east with a speed of $5 m / s$ crosses the train. The time taken by the bird to cross the train will be

1 16 sec

2 12 sec

3 10 sec

4 8 sec

Explanation:

d
Relative velocity $= 10 + 5 = 15 m / s$
Time taken by the bird to cross the train
$= \frac{120}{15} = 8 \sec .$

**NCERT-XI-I-14**

TEST SERIES (PHYSICS FST)

266472 Energy of photon whose frequency is $10^{12} MHz$ , will be

1

4.14 \times 10^{3} KeV

2

4.14 \times 10^{2} KeV

3

4.14 \times 10^{3} MeV

4

4.14 \times 10^{3} eV

Explanation:

d
$\begin{aligned} E (eV) & = \frac{hv}{e} = \frac{6.6 \times 10^{- 24} \times 10^{12} \times 10^{6}}{1.6 \times 10^{- 19}} \\ = 4.14 \times 10^{3} eV \end{aligned}$

**NCERT-XII-II-283**

TEST SERIES (PHYSICS FST)

266473 Astep-down transformer is used on a 1000 V line to delinear 20 A at 120 V at the secondary coil. If the efficiency of the transformer is $80 %$ the current drawn from the line is

1 3 A

2 30 A

3 0.3 A

4 2.4 A

Explanation:

a
$\begin{aligned} η & = \frac{Output}{Input} \Rightarrow \frac{80}{100} = \frac{20 \times 20}{1000 \times i_{1}} \\ \Rightarrow i_{1} & = \frac{20 \times 120 \times 100}{1000 \times 80} \\ i_{1} & = 3 A \end{aligned}$

**NCERT-XII-I-139**

TEST SERIES (PHYSICS FST)

266474 A uniform electric field $E$ exists along positive x -axis. The work done in moving a charge 0.5 C through a distance 2 m along a direction making an angle $60^{\circ}$ with x -axis is 10 J . Then the magnitude of electric field is :

1

5 V^{- 1}

2

2 V m^{- 1}

3

\sqrt{5} v^{- 1}

4

20 {Vm}^{- 1}

Explanation:

d
Force acting on the charged particle due to electric fiel $d = q E$
Work done in moving through distance S,
$\begin{aligned} W & = q \vec{E} . S \\ = (q E) \times (S) \times (\cos θ) \\ ∴ 10 J & = (0.5) \times E \times 2 \cos 60^{\circ} \\ E & = 10 \times 2 = 20 {NC}^{- 1} \\ = 20 {Vm}^{- 1} \end{aligned}$

**NCERT-XII-I-14**

TEST SERIES (PHYSICS FST)

266469 Assertion: Young's modulus for a perfectly plastic body is zero. Reason: For a perfectly plastic body, restoring force is zero.

1 Assertion is correct, reason is correct; reason is a correct explanation for assertion.

2 Assertion is correct, reason is correct; reason is not a correct explanation for assertion.

3 Assertion is correct, reason is incorrect.

4 Assertion is incorrect, reason is incorrect.

Explanation:

a
Young's modulus of a material
$Y = \frac{Stress}{Strain}$
Here, Stress $= \frac{Restoring force}{Area}$
As restoring force is zero.
$∴ Y = 0$

**NCERT-XI-II-170**

TEST SERIES (PHYSICS FST)

266470 A 120 m long train is moving towards west with a speed of 10 ms . A bird flying east with a speed of $5 m / s$ crosses the train. The time taken by the bird to cross the train will be

1 16 sec

2 12 sec

3 10 sec

4 8 sec

Explanation:

d
Relative velocity $= 10 + 5 = 15 m / s$
Time taken by the bird to cross the train
$= \frac{120}{15} = 8 \sec .$

**NCERT-XI-I-14**

TEST SERIES (PHYSICS FST)

266472 Energy of photon whose frequency is $10^{12} MHz$ , will be

1

4.14 \times 10^{3} KeV

2

4.14 \times 10^{2} KeV

3

4.14 \times 10^{3} MeV

4

4.14 \times 10^{3} eV

Explanation:

d
$\begin{aligned} E (eV) & = \frac{hv}{e} = \frac{6.6 \times 10^{- 24} \times 10^{12} \times 10^{6}}{1.6 \times 10^{- 19}} \\ = 4.14 \times 10^{3} eV \end{aligned}$

**NCERT-XII-II-283**

TEST SERIES (PHYSICS FST)

266473 Astep-down transformer is used on a 1000 V line to delinear 20 A at 120 V at the secondary coil. If the efficiency of the transformer is $80 %$ the current drawn from the line is

1 3 A

2 30 A

3 0.3 A

4 2.4 A

Explanation:

a
$\begin{aligned} η & = \frac{Output}{Input} \Rightarrow \frac{80}{100} = \frac{20 \times 20}{1000 \times i_{1}} \\ \Rightarrow i_{1} & = \frac{20 \times 120 \times 100}{1000 \times 80} \\ i_{1} & = 3 A \end{aligned}$

**NCERT-XII-I-139**

TEST SERIES (PHYSICS FST)

266474 A uniform electric field $E$ exists along positive x -axis. The work done in moving a charge 0.5 C through a distance 2 m along a direction making an angle $60^{\circ}$ with x -axis is 10 J . Then the magnitude of electric field is :

1

5 V^{- 1}

2

2 V m^{- 1}

3

\sqrt{5} v^{- 1}

4

20 {Vm}^{- 1}

Explanation:

d
Force acting on the charged particle due to electric fiel $d = q E$
Work done in moving through distance S,
$\begin{aligned} W & = q \vec{E} . S \\ = (q E) \times (S) \times (\cos θ) \\ ∴ 10 J & = (0.5) \times E \times 2 \cos 60^{\circ} \\ E & = 10 \times 2 = 20 {NC}^{- 1} \\ = 20 {Vm}^{- 1} \end{aligned}$

**NCERT-XII-I-14**

TEST SERIES (PHYSICS FST)

266469 Assertion: Young's modulus for a perfectly plastic body is zero. Reason: For a perfectly plastic body, restoring force is zero.

1 Assertion is correct, reason is correct; reason is a correct explanation for assertion.

2 Assertion is correct, reason is correct; reason is not a correct explanation for assertion.

3 Assertion is correct, reason is incorrect.

4 Assertion is incorrect, reason is incorrect.

Explanation:

a
Young's modulus of a material
$Y = \frac{Stress}{Strain}$
Here, Stress $= \frac{Restoring force}{Area}$
As restoring force is zero.
$∴ Y = 0$

**NCERT-XI-II-170**

TEST SERIES (PHYSICS FST)

266470 A 120 m long train is moving towards west with a speed of 10 ms . A bird flying east with a speed of $5 m / s$ crosses the train. The time taken by the bird to cross the train will be

1 16 sec

2 12 sec

3 10 sec

4 8 sec

Explanation:

d
Relative velocity $= 10 + 5 = 15 m / s$
Time taken by the bird to cross the train
$= \frac{120}{15} = 8 \sec .$

**NCERT-XI-I-14**

TEST SERIES (PHYSICS FST)

266472 Energy of photon whose frequency is $10^{12} MHz$ , will be

1

4.14 \times 10^{3} KeV

2

4.14 \times 10^{2} KeV

3

4.14 \times 10^{3} MeV

4

4.14 \times 10^{3} eV

Explanation:

d
$\begin{aligned} E (eV) & = \frac{hv}{e} = \frac{6.6 \times 10^{- 24} \times 10^{12} \times 10^{6}}{1.6 \times 10^{- 19}} \\ = 4.14 \times 10^{3} eV \end{aligned}$

**NCERT-XII-II-283**

TEST SERIES (PHYSICS FST)

266473 Astep-down transformer is used on a 1000 V line to delinear 20 A at 120 V at the secondary coil. If the efficiency of the transformer is $80 %$ the current drawn from the line is

1 3 A

2 30 A

3 0.3 A

4 2.4 A

Explanation:

a
$\begin{aligned} η & = \frac{Output}{Input} \Rightarrow \frac{80}{100} = \frac{20 \times 20}{1000 \times i_{1}} \\ \Rightarrow i_{1} & = \frac{20 \times 120 \times 100}{1000 \times 80} \\ i_{1} & = 3 A \end{aligned}$

**NCERT-XII-I-139**

TEST SERIES (PHYSICS FST)

266474 A uniform electric field $E$ exists along positive x -axis. The work done in moving a charge 0.5 C through a distance 2 m along a direction making an angle $60^{\circ}$ with x -axis is 10 J . Then the magnitude of electric field is :

1

5 V^{- 1}

2

2 V m^{- 1}

3

\sqrt{5} v^{- 1}

4

20 {Vm}^{- 1}

Explanation:

d
Force acting on the charged particle due to electric fiel $d = q E$
Work done in moving through distance S,
$\begin{aligned} W & = q \vec{E} . S \\ = (q E) \times (S) \times (\cos θ) \\ ∴ 10 J & = (0.5) \times E \times 2 \cos 60^{\circ} \\ E & = 10 \times 2 = 20 {NC}^{- 1} \\ = 20 {Vm}^{- 1} \end{aligned}$

**NCERT-XII-I-14**

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