The power radiated by a black body is \(P\) and it radiates maximum energy at wavelength \(\lambda_0\). Temperature of the black body is now changed so that it radiates maximum energy at the wavelength \(\frac{3}{4}\lambda_0\). The power radiated by it now becomes \(nP\). The value of \(n\) is:
1. \( \frac{3}{4} \)
2. \( \frac{4}{3} \)
3. \( \frac{256}{81} \)
4. \( \frac{81}{256}\)

Subtopic:  Wien's Displacement Law |
 65%
From NCERT
NEET - 2018
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A spherical black body with a radius of 12 cm radiates 450-watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watts would be:

1. 225 2. 450
3. 1000 4. 1800
Subtopic:  Stefan-Boltzmann Law |
 74%
From NCERT
NEET - 2017
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Two rods \(A\) and \(B\) of different materials are welded together as shown in the figure. Their thermal conductivities are \(K_1\) and \(K_2.\) The thermal conductivity of the composite rod will be:
            
1. \(\frac{3(K_1+K_2)}{2}\)
2. \(K_1+K_2\)
3. \(2(K_1+K_2)\)
4. \(\frac{(K_1+K_2)}{2}\)

Subtopic:  Conduction |
 70%
From NCERT
NEET - 2017
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A piece of ice falls from a height \(h\) so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice, and all energy of ice gets converted into heat during its fall. The value of \(h\) is: (Latent heat of ice is \(3.4\times10^5\) J/kg and \(g=10\) N/kg)

1. \(544\) km 2. \(136\) km
3. \(68\)  km 4. \(34\) km
Subtopic:  Calorimetry |
 75%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at \(100~^{\circ}\mathrm{C}\), while the other one is at \(0~^{\circ}\mathrm{C}.\) If the two bodies are brought into contact, then assuming no heat loss, the final common temperature is:

1. \(50~^{\circ}\mathrm{C}\)
2. more than \(50~^{\circ}\mathrm{C}\)
3. less than \(50~^{\circ}\mathrm{C}\) but greater than \(0~^{\circ}\mathrm{C}\)
4. \(0~^{\circ}\mathrm{C}\)
Subtopic:  Calorimetry |
 65%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A body cools from a temperature of \(3T\) to \(2T\) in \(10\) minutes. The room temperature is \(T\). Assuming that Newton's law of cooling is applicable, the temperature of the body at the end of the next \(10\) minutes will be:
1. \(\frac{7}{4}T\)
2. \(\frac{3}{2}T\)
3. \(\frac{4}{3}T\)
4. \(T\)

Subtopic:  Newton's Law of Cooling |
 72%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

The coefficient of linear expansion of brass and steel rods are \(\alpha_1\) and \(\alpha_2\). Lengths of brass and steel rods are \(L_1\) and \(L_2\) respectively. If \((L_2-L_1)\) remains the same at all temperatures, which one of the following relations holds good?
1. \(\alpha_1L_2^2=\alpha_2L_1^2\)
2. \(\alpha_1^2L_2=\alpha_2^2L_1\)
3. \(\alpha_1L_1=\alpha_2L_2\)
4. \(\alpha_1L_2=\alpha_2L_1\)

Subtopic:  Thermal Expansion |
 88%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A black body is at a temperature of \(5760~\mathrm{K}\). The energy of radiation emitted by the body at wavelength \(250~\mathrm{nm}\) is \(U_1\), at wavelength \(500~\mathrm{nm}\) is \(U_2\) and that at \(1000~\mathrm{nm}\) is \(U_3\). Wien’s constant, \(\mathrm{b}=2.88 \times 10^6 \mathrm{~nm}-\mathrm{K}\). Which of the following is correct?
1. \( \mathrm{U}_3 =0 \)
2. \(\mathrm{U}_1 >\mathrm{U}_2 \)
3. \(\mathrm{U}_2 >\mathrm{U}_1 \)
4. \(\mathrm{U}_1 =0\)
Subtopic:  Wien's Displacement Law |
 66%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh

A piece of ice falls from a height \(h\) so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice. The value of \(h\) is:
[Latent heat of ice is \(3.4 \times 10^5~\mathrm{~J/kg}\) and \(g=10~\mathrm{N/kg}\)]
1. \(544~\mathrm{km}\) 
2. \(136~\mathrm{km}\) 
3. \(68~\mathrm{km}\) 
4. \(34~\mathrm{km}\) 
 
Subtopic:  Calorimetry |
 81%
From NCERT
NEET - 2016
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh
Hints
Links
To view explanation, please take trial in the course.
NEET 2023 - Target Batch - Aryan Raj Singh