MHT CET 202626 AprilMorning Shift
- Exam
- MHT CET
- Year
- 2026
- Date
- 26 April
- Shift
- Morning Shift
- Subject
- Physics
- Chapter
- Thermal Properties of Matter
MHT CET 2026 · 26 April · Morning Shift · Physics · Thermal Properties of Matter
A cylindrical rod with one end in a steam chamber and the other end...
A cylindrical rod with one end in a steam chamber and the other end in ice results in melting of gram of ice per second. If the rod is replaced by another with half the length and double the radius of the first, the thermal conductivity of the material of second rod is that of first, the rate at which ice melts in gram per second will be (Latent heat of ice cal/g)
Options
- A
- B
- C
- D
Correct answer
C.
Step-by-step solution
The rate of heat flow through a rod is given by .
The rate of melting of ice is , where is the latent heat of fusion.
For the first rod, the rate of melting is:
For the second rod, the given parameters are , , and .
The rate of melting for the second rod is:
Substituting the values of , , and :
m_2 = \dfrac{\left(\dfrac{K_1}{4}\right)^{4} \pi r_1^2 \Delta T}{\dfrac{L_1}{2} L_f}m_2 = \dfrac{K_1 \pi r_1^2 \Delta T}{\dfrac{L_1}{2} L_f} = 2 \left( \dfrac{K_1 \pi r_1^2 \Delta T}{L_1 L_f} \right)
\times0.1 = 0.2 \text{ g/s}
Answer: 0.2
The rate of melting of ice is , where is the latent heat of fusion.
For the first rod, the rate of melting is:
For the second rod, the given parameters are , , and .
The rate of melting for the second rod is:
Substituting the values of , , and :
m_2 = \dfrac{\left(\dfrac{K_1}{4}\right)^{4} \pi r_1^2 \Delta T}{\dfrac{L_1}{2} L_f}m_2 = \dfrac{K_1 \pi r_1^2 \Delta T}{\dfrac{L_1}{2} L_f} = 2 \left( \dfrac{K_1 \pi r_1^2 \Delta T}{L_1 L_f} \right)
\times0.1 = 0.2 \text{ g/s}
Answer: 0.2