UPSC Prelims Full Length Test - 71

Which of the following statements is/are correct?

1. When a glass rod is rubbed with silk, a negative charge develops on silk.
2. When an ebonite rod is rubbed with fur, a negative charge develops on fur.

Select the correct option from the codes given below:

Which of the following appear to display different colours primarily due to the phenomenon of interference?

1. Soap bubble
2. Rainbow
3. Oil slick on wet road

Select the correct option from the codes given below:

Consider a motorboat directed upstream and observed to be at rest from the bank of a river. Which of the following statements is/are correct in this context?

1. The engine of the boat is doing work as per Physics.
2. If the engine stops, no work will be done.
3. If the engine stops, the boat will gain kinetic energy.

Select the correct option from the codes given below:

With reference to geostationary and geosynchronous orbits, consider the following statements:

1. Geostationary orbit must be circular, whereas geosynchronous orbit may not be circular.
2. Geostationary orbit is directly above the equator, while geosynchronous orbit is not necessarily above the equator.
3. There is only one geostationary orbit, but there can be many geosynchronous orbits.

Select the correct option from the codes given below:

Consider the following statements regarding the modes of heat transfer:

1. In conduction, there is no actual movement of molecules, whereas in convection, heat is transferred by the actual movement of molecules.
2. Transfer of heat by conduction generally occurs in solids, while transfer by convection occurs primarily in liquids and gases.

Which of the above statements is/are correct?