MCQOPTIONS
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MCQOPTIONS
This section includes 9 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering Physics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A particle with a lifetime of 2 X 10-6 s moves through the laboratory with a speed of 0.9 c. It s lifetime, as measured by an observer in the laboratory, is ___________ |
| A. | 2 X 10<sup>-6</sup> s |
| B. | 3.2 X 10<sup>-6</sup> s |
| C. | 4.6 X 10<sup>-6</sup> s |
| D. | 5.4 X 10<sup>-6</sup> s |
| Answer» D. 5.4 X 10<sup>-6</sup> s | |
| 2. |
A rod of length 1m moves with a speed of 0.5 c. How much length contraction takes place? |
| A. | 50 % |
| B. | 14 % |
| C. | 10 % |
| D. | 35 % |
| Answer» C. 10 % | |
| 3. |
A cube with sides of proper length lo is viewed from a reference frame moving with velocity v, parallel to an edge of the cube. The expression for the volume of the cube for the observer is __________ |
| A. | L<sub>o</sub><sup>3</sup> |
| B. | L<sub>o</sub><sup>3</sup> ( sqrt{1- frac{v^2}{c^2}} ) |
| C. | L<sub>o</sub><sup>3</sup> ((1- frac{v^2}{c^2})^{3/2} ) |
| D. | L<sub>o</sub><sup>3</sup> ((1- frac{v^2}{c^2}) ) |
| Answer» B. L<sub>o</sub><sup>3</sup> ( sqrt{1- frac{v^2}{c^2}} ) | |
| 4. |
How fast does a rocket have to move relative to an observer for its length to be contracted to 95% of its original length? |
| A. | 0.5 c |
| B. | 0.4 c |
| C. | 0.3 c |
| D. | 0.2 c |
| Answer» D. 0.2 c | |
| 5. |
An object of length 1 m is moving at speed 0.5c. To an observer at rest relative to the object, the length of the object seems to be ___________ |
| A. | 0.86 m |
| B. | 0.5 m |
| C. | 1 m |
| D. | 0.14 m |
| Answer» D. 0.14 m | |
| 6. |
The length of a rod seems shorter to an observer when it moves in a specific direction. What change would he observe when the direction of rod changes by 180o? |
| A. | The rod becomes even smaller |
| B. | The length of the rod increases |
| C. | The length of the rod remains the same |
| D. | The rod has the length equal to its proper length |
| Answer» D. The rod has the length equal to its proper length | |
| 7. |
A 20-year-old person goes at a high speed in a rocket on his birthday. when he comes back to earth after 1 earth year, he would be ___________ |
| A. | 1 year older |
| B. | 2 years older |
| C. | A few months older |
| D. | Same age |
| Answer» D. Same age | |
| 8. |
If an object reaches the speed of light, it s length changes to ___________ |
| A. | Infinite |
| B. | Double of the value |
| C. | Half of the value |
| D. | Zero |
| Answer» E. | |
| 9. |
A rod of length 5 m is moving at a speed of 0.6 c. To an observer sitting perpendicular to the direction of motion, the length appears to be _______________ |
| A. | 5 m |
| B. | 4 m |
| C. | 3 m |
| D. | 2 m |
| Answer» B. 4 m | |