A nucleus with mass number \(240\) breaks into fragments each of mass number \(120.\) The binding energy per nucleon of unfragmented nuclei is \(7.6~\text{MeV}\) while that of fragments is \(8.5~\text{MeV}.\) The total gain in the binding energy in the process is:

1. \(804~\text{MeV}\) 2. \(216~\text{MeV}\)
3. \(0.9~\text{MeV}\) 4. \(9.4~\text{MeV}\)

Subtopic:  Nuclear Binding Energy |
 65%
Level 2: 60%+
NEET - 2021
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Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional force are 10% of the input energy. How much power is generated by the turbine? g=10 m/s2

1. 12.3 kW  2. 7.0 kW 
3. 10.2 kW  4. 8.1 kW
Subtopic:  Power |
 72%
Level 2: 60%+
NEET - 2021
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A convex lens \({A}\) of focal length \(20~\text{cm}\) and a concave lens \({B}\) of focal length \(5~\text{cm}\) are kept along the same axis with a distance \(d\) between them. If a parallel beam of light falls on \(A\) leaves \(B\) as a parallel beam, then the distance \(d\) in \((\text{cm})\) will be: 
1. \(50\)
2. \(30\)
3. \(25\)
4. \(15\)

Subtopic:  Lenses |
Level 3: 35%-60%
NEET - 2021
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A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since:

1. a large aperture contributes to the quality and visibility of the images.
2. a large area of the objective ensures better light-gathering power.
3. a large aperture provides a better resolution.
4. all of the above.

Subtopic:  Telescope |
 80%
Level 1: 80%+
NEET - 2021
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The electron concentration in an \(\mathrm{n\text-}\)type semiconductor is the same as the hole concentration in a \(\mathrm{p\text{-}}\)type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.

1. current in \(\mathrm{n\text-}\)type \(>\) current in \(\mathrm{p\text{-}}\)type.
2. no current will flow in \(\mathrm{p\text{-}}\)type, current will only flow in \(\mathrm{n\text-}\)type.
3. current in \(\mathrm{n\text-}\)type \(=\) current in \(\mathrm{p\text{-}}\)type.
4. current in \(\mathrm{p\text{-}}\)type \(>\) current in \(\mathrm{n\text-}\)type.
Subtopic:  Types of Semiconductors |
 52%
Level 3: 35%-60%
NEET - 2021
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If a body is executing simple harmonic motion with frequency \(n\), then the frequency of its potential energy is:
1. \(3n\) 2. \(4n\)
3. \(n\) 4. \(2n\)
Subtopic:  Energy of SHM |
 72%
Level 2: 60%+
NEET - 2021
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A cup of coffee cools from \(90^{\circ}\text{C}\) to \(80^{\circ}\text{C}\) in \(t\) minutes, when the room temperature is \(20^{\circ}\text{C}.\) The time taken by a similar cup of coffee to cool from \(80^{\circ}\text{C}\) to \(60^{\circ}\text{C}\) at room temperature same at \(20^{\circ}\text{C}\) is:

1. \(\dfrac{10}{13}t\) 2. \(\dfrac{5}{13}t\)
3. \(\dfrac{13}{10}t\) 4. \(\dfrac{13}{5}t\)
Subtopic:  Newton's Law of Cooling |
 65%
Level 2: 60%+
NEET - 2021
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In a potentiometer circuit, a cell of emf \(1.5~\text{V}\) gives a balance point at 36 cm length of wire. If another cell of emf 2.5 V replaces the first cell, then at what length of the wire, the balance point occur? 
1. 64 cm 
2. 62 cm 
3. 60 cm 
4. 21.6 cm

 75%
Level 2: 60%+
NEET - 2021
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The effective resistance of a parallel connection that consists of four wires of equal length, equal area of cross-section, and same material is \(0.25~\Omega\). What will be the effective resistance if they are connected in series?
1. \(1~\Omega\) 
2. \(4~\Omega\)
3. \(0.25~\Omega\)
4. \(0.5~\Omega\)

Subtopic:  Combination of Resistors |
 72%
Level 2: 60%+
NEET - 2021
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A radioactive nucleus \(_{\mathrm{Z}}^{\mathrm{A}}\mathrm{X}\) undergoes spontaneous decay in the sequence \(_{\mathrm{Z}}^{\mathrm{A}}\mathrm{X}\rightarrow \mathrm{B}_{\mathrm{Z-1}}\rightarrow \mathrm{C}_{\mathrm{Z-3}}\rightarrow \mathrm{D}_{\mathrm{Z-2}}\) where \(\mathrm{Z}\) is the atomic number of element \(\mathrm{X}.\) The possible decay particles in the sequence are: 
1. \(\beta^{+}, ~\alpha, ~\beta^{-}\) 2. \(\beta^{-}, ~\alpha, ~\beta^{+}\)
3. \(\alpha, ~\beta^{-},~\beta^{+}\) 4. \(\alpha, ~\beta^{+},~\beta^{-}\)
Subtopic:  Types of Decay |
 74%
Level 2: 60%+
NEET - 2021
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