A copper rod of \(88\) cm and an aluminium rod of an unknown length have an equal increase in their lengths independent of an increase in temperature. The length of the aluminium rod is:
\(\left(\alpha_{Cu}= 1.7\times10^{-5}~\text{K}^{-1}~\text{and}~\alpha_{Al}= 2.2\times10^{-5}~\text{K}^{-1}\right)\)

1. \(68~\text{cm}\) 2. \(6.8~\text{cm}\)
3. \(113.9~\text{cm}\) 4. \(88~\text{cm}\)
Subtopic:  Thermal Expansion |
 80%
Level 1: 80%+
NEET - 2019
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The unit of thermal conductivity is:
1. W m–1 K–1 2. J m K–1
3. J m–1 K–1 4. W m K–1
Subtopic:  Dimensions |
 59%
Level 3: 35%-60%
NEET - 2019
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For a \(\mathrm{p}\text{-}\)type semiconductor, which of the following statements is true?

1. Electrons are the majority carriers and pentavalent atoms are the dopants.
2. Electrons are the majority carriers and trivalent atoms are the dopants.
3. Holes are the majority carriers and trivalent atoms are the dopants.
4. Holes are the majority carriers and pentavalent atoms are the dopants.
Subtopic:  Types of Semiconductors |
 83%
Level 1: 80%+
NEET - 2019
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A cylindrical conductor of radius \(R\) is carrying a constant current. The plot of the magnitude of the magnetic field \(B\) with the distance \(d\) from the centre of the conductor is correctly represented by the figure:

1. 2.
3. 4.
Subtopic:  Ampere Circuital Law |
 70%
Level 2: 60%+
NEET - 2019
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Body \(\mathrm{A}\) of mass \(4m\) moving with speed \(u\) collides with another body \(\mathrm{B}\) of mass \(2m\) at rest. The collision is head-on and elastic in nature. After the collision, the fraction of energy lost by the colliding body \(\mathrm{A}\) is:

1. \(\dfrac{5}{9}\) 2. \(\dfrac{1}{9}\)
3. \(\dfrac{8}{9}\) 4. \(\dfrac{4}{9}\)
Subtopic:  Collisions |
 66%
Level 2: 60%+
NEET - 2019
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The correct Boolean operation represented by the circuit diagram given above is:
 
1. \(\mathrm{NOR}\)
2. \(\mathrm{AND}\)
3. \(\mathrm{OR}\)
4. \(\mathrm{NAND}\)

Subtopic:  Logic gates |
 53%
Level 3: 35%-60%
NEET - 2019
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When an object is shot from the bottom of a long, smooth inclined plane kept at an angle of \(60^\circ\) with horizontal, it can travel a distance \(x_1\) along the plane. But when the inclination is decreased to \(30^\circ\) and the same object is shot with the same velocity, it can travel \(x_2\) distance. Then \(x_1:x_2\) will be:

1. \(1:2\sqrt{3}\) 2. \(1:\sqrt{2}\)
3. \(\sqrt{2}:1\) 4. \(1:\sqrt{3}\)
Subtopic:  Conservation of Mechanical Energy |
 76%
Level 2: 60%+
NEET - 2019
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The work done to raise a mass \(m\) from the surface of the earth to a height \(h\), which is equal to the radius of the earth, is:
1. \(\dfrac{3}{2}mgR\) 2. \(mgR\)
3. \(2mgR\) 4. \(\dfrac{1}{2}mgR\)
Subtopic:  Gravitational Potential Energy |
 67%
Level 2: 60%+
NEET - 2019
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The total energy of an electron in the orbit of an atom is \(-3.4~\text{eV}.\) Its kinetic and potential energies are, respectively:
1. \(3.4~\text{eV},~3.4~\text{eV}\)
2. \(-3.4~\text{eV},~-3.4~\text{eV}\)
3. \(-3.4~\text{eV},~-6.8~\text{eV}\)
4. \(3.4~\text{eV},~-6.8~\text{eV}\)
Subtopic:  Bohr's Model of Atom |
 87%
Level 1: 80%+
NEET - 2019
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In which of the following processes, the heat is neither absorbed nor released by a system?
1. isochoric 2. isothermal
3. adiabatic 4. isobaric
Subtopic:  Types of Processes |
 89%
Level 1: 80%+
NEET - 2019
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