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 \[ \mathrm{Y}=\frac{\text { Stress }}{\text { Strain }} \] Here, Stress \(=\frac{\text { Restoring force }}{\text { Area }}\) As restoring force is zero. \[ \therefore Y=0 \]
**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 \(5 \mathrm{~m} / \mathrm{s}\) 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 \(=10+5=15 \mathrm{~m} / \mathrm{s}\) Time taken by the bird to cross the train \[ =\frac{120}{15}=8 \mathrm{sec} . \]
**NCERT-XI-I-14**
TEST SERIES (PHYSICS FST)
266472
Energy of photon whose frequency is \(10^{12} \mathrm{MHz}\), will be
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
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 \(5 \mathrm{~V}^{-1}\)
2 \(2 \mathrm{~V} \mathrm{~m}^{-1}\)
3 \(\sqrt{5} \mathrm{v}^{-1}\)
4 \(20 \mathrm{Vm}^{-1}\)
Explanation:
d Force acting on the charged particle due to electric fiel \(\mathrm{d}=\mathrm{q} \mathbf{E}\) Work done in moving through distance S, \[ \begin{aligned} W & =q \vec{E} . \mathbf{S} \\ & =(q E) \times(S) \times(\cos \theta) \\ \therefore \quad 10 \mathrm{~J} & =(0.5) \times E \times 2 \cos 60^{\circ} \\ E & =10 \times 2=20 \mathrm{NC}^{-1} \\ & =20 \mathrm{Vm}^{-1} \end{aligned} \]
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 \[ \mathrm{Y}=\frac{\text { Stress }}{\text { Strain }} \] Here, Stress \(=\frac{\text { Restoring force }}{\text { Area }}\) As restoring force is zero. \[ \therefore Y=0 \]
**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 \(5 \mathrm{~m} / \mathrm{s}\) 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 \(=10+5=15 \mathrm{~m} / \mathrm{s}\) Time taken by the bird to cross the train \[ =\frac{120}{15}=8 \mathrm{sec} . \]
**NCERT-XI-I-14**
TEST SERIES (PHYSICS FST)
266472
Energy of photon whose frequency is \(10^{12} \mathrm{MHz}\), will be
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
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 \(5 \mathrm{~V}^{-1}\)
2 \(2 \mathrm{~V} \mathrm{~m}^{-1}\)
3 \(\sqrt{5} \mathrm{v}^{-1}\)
4 \(20 \mathrm{Vm}^{-1}\)
Explanation:
d Force acting on the charged particle due to electric fiel \(\mathrm{d}=\mathrm{q} \mathbf{E}\) Work done in moving through distance S, \[ \begin{aligned} W & =q \vec{E} . \mathbf{S} \\ & =(q E) \times(S) \times(\cos \theta) \\ \therefore \quad 10 \mathrm{~J} & =(0.5) \times E \times 2 \cos 60^{\circ} \\ E & =10 \times 2=20 \mathrm{NC}^{-1} \\ & =20 \mathrm{Vm}^{-1} \end{aligned} \]
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 \[ \mathrm{Y}=\frac{\text { Stress }}{\text { Strain }} \] Here, Stress \(=\frac{\text { Restoring force }}{\text { Area }}\) As restoring force is zero. \[ \therefore Y=0 \]
**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 \(5 \mathrm{~m} / \mathrm{s}\) 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 \(=10+5=15 \mathrm{~m} / \mathrm{s}\) Time taken by the bird to cross the train \[ =\frac{120}{15}=8 \mathrm{sec} . \]
**NCERT-XI-I-14**
TEST SERIES (PHYSICS FST)
266472
Energy of photon whose frequency is \(10^{12} \mathrm{MHz}\), will be
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
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 \(5 \mathrm{~V}^{-1}\)
2 \(2 \mathrm{~V} \mathrm{~m}^{-1}\)
3 \(\sqrt{5} \mathrm{v}^{-1}\)
4 \(20 \mathrm{Vm}^{-1}\)
Explanation:
d Force acting on the charged particle due to electric fiel \(\mathrm{d}=\mathrm{q} \mathbf{E}\) Work done in moving through distance S, \[ \begin{aligned} W & =q \vec{E} . \mathbf{S} \\ & =(q E) \times(S) \times(\cos \theta) \\ \therefore \quad 10 \mathrm{~J} & =(0.5) \times E \times 2 \cos 60^{\circ} \\ E & =10 \times 2=20 \mathrm{NC}^{-1} \\ & =20 \mathrm{Vm}^{-1} \end{aligned} \]
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 \[ \mathrm{Y}=\frac{\text { Stress }}{\text { Strain }} \] Here, Stress \(=\frac{\text { Restoring force }}{\text { Area }}\) As restoring force is zero. \[ \therefore Y=0 \]
**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 \(5 \mathrm{~m} / \mathrm{s}\) 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 \(=10+5=15 \mathrm{~m} / \mathrm{s}\) Time taken by the bird to cross the train \[ =\frac{120}{15}=8 \mathrm{sec} . \]
**NCERT-XI-I-14**
TEST SERIES (PHYSICS FST)
266472
Energy of photon whose frequency is \(10^{12} \mathrm{MHz}\), will be
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
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 \(5 \mathrm{~V}^{-1}\)
2 \(2 \mathrm{~V} \mathrm{~m}^{-1}\)
3 \(\sqrt{5} \mathrm{v}^{-1}\)
4 \(20 \mathrm{Vm}^{-1}\)
Explanation:
d Force acting on the charged particle due to electric fiel \(\mathrm{d}=\mathrm{q} \mathbf{E}\) Work done in moving through distance S, \[ \begin{aligned} W & =q \vec{E} . \mathbf{S} \\ & =(q E) \times(S) \times(\cos \theta) \\ \therefore \quad 10 \mathrm{~J} & =(0.5) \times E \times 2 \cos 60^{\circ} \\ E & =10 \times 2=20 \mathrm{NC}^{-1} \\ & =20 \mathrm{Vm}^{-1} \end{aligned} \]
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 \[ \mathrm{Y}=\frac{\text { Stress }}{\text { Strain }} \] Here, Stress \(=\frac{\text { Restoring force }}{\text { Area }}\) As restoring force is zero. \[ \therefore Y=0 \]
**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 \(5 \mathrm{~m} / \mathrm{s}\) 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 \(=10+5=15 \mathrm{~m} / \mathrm{s}\) Time taken by the bird to cross the train \[ =\frac{120}{15}=8 \mathrm{sec} . \]
**NCERT-XI-I-14**
TEST SERIES (PHYSICS FST)
266472
Energy of photon whose frequency is \(10^{12} \mathrm{MHz}\), will be
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
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 \(5 \mathrm{~V}^{-1}\)
2 \(2 \mathrm{~V} \mathrm{~m}^{-1}\)
3 \(\sqrt{5} \mathrm{v}^{-1}\)
4 \(20 \mathrm{Vm}^{-1}\)
Explanation:
d Force acting on the charged particle due to electric fiel \(\mathrm{d}=\mathrm{q} \mathbf{E}\) Work done in moving through distance S, \[ \begin{aligned} W & =q \vec{E} . \mathbf{S} \\ & =(q E) \times(S) \times(\cos \theta) \\ \therefore \quad 10 \mathrm{~J} & =(0.5) \times E \times 2 \cos 60^{\circ} \\ E & =10 \times 2=20 \mathrm{NC}^{-1} \\ & =20 \mathrm{Vm}^{-1} \end{aligned} \]
