MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Two spheres, A & B, are made up of the same material. The radius of A is twice that of B, while the temperature of A is half that of B. What is their ratio of energy emitted per unit time (EA : EB)? |
| A. | 1 |
| B. | 1/4 |
| C. | 1/2 |
| D. | 1/16 |
| Answer» C. 1/2 | |
| 2. |
If we hold a metal rod from one end and dip the other in a source of fire, what will happen to the temperature of the rod at steady state? |
| A. | Be uniform |
| B. | Decrease with time |
| C. | Remain constant at a single value throughout the length of the rod |
| D. | Stay nonuniform |
| Answer» E. | |
| 3. |
The sun emits light having maximum intensity at a wavelength 468nm. Assume emissivity of sun is 1. Calculate its surface temperature. = 5.67*10-8W/m2K4. |
| A. | 6800K |
| B. | 3400K |
| C. | 6196K |
| D. | 7200K |
| Answer» D. 7200K | |
| 4. |
What is the net amount of energy per unit time being received by a body having a temperature of 40 C in a surrounding of 60 C? (The surface area of body = 2m2, = 5.67*10-8W/ m2K4 & emissivity of 0.4). |
| A. | 122.4W |
| B. | 0.47W |
| C. | 33W |
| D. | 86W |
| Answer» B. 0.47W | |
| 5. |
The electromagnetic energy emitted by a perfect radiator corresponding to a temperature T and surface area A is? |
| A. | A T<sup>4</sup> t, in unit time t |
| B. | Ae T<sup>4</sup> t, in unit time t |
| C. | Ae4 c) Ae T<sup>4</sup> |
| D. | A T<sup>4</sup> |
| Answer» B. Ae T<sup>4</sup> t, in unit time t | |
| 6. |
What is the value of Wien s constant? |
| A. | 2.9*10<sup>-3</sup>mK |
| B. | 2.9*10<sup>-4</sup>mK |
| C. | 2.9*10<sup>-3</sup>cmK |
| D. | 2.9*10<sup>-4</sup>cmK |
| Answer» B. 2.9*10<sup>-4</sup>mK | |
| 7. |
At a given temperature a body emits energy of a single wavelength corresponding to that temperature. True or False? |
| A. | True |
| B. | False |
| Answer» C. | |
| 8. |
What is the expression for heat current? Q is heat, t is time, T is temperature. |
| A. | Q/ t |
| B. | Q/ T |
| C. | T/ t |
| D. | Q/ T t |
| Answer» B. Q/ T | |
| 9. |
A steel and a copper bar are joined end to end. The area of the steel bar is half the area of the copper bar. Their lengths are equal to 10cm each. Temperature of free ends of steel & copper rod are 0 C & 100 C respectively. KS = 50 J/smK & KC =384 J/smK. Calculate equivalent thermal conductivity of the combined bar. |
| A. | 63 C |
| B. | 63K |
| C. | 336 C |
| D. | 36K |
| Answer» B. 63K | |
| 10. |
Quantitatively heat conduction can be described as? |
| A. | Heat flow for a given temperature difference |
| B. | Time rate of heat flow for a given temperature difference |
| C. | Temperature difference caused due to heat flow per unit time |
| D. | Temperature difference per unit quantity of heat transferred |
| Answer» C. Temperature difference caused due to heat flow per unit time | |
| 11. |
When water is kept in a very hot pan, the entire water heats up. Which mode of heat transfer is responsible for this? |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Convection along with radiation |
| Answer» C. Radiation | |