Physics - Study Mode
[#1226] Water drops cannot stick to the oily surface due to
Correct Answer
(B) Surface tension
Explanation
Solution: The separation of oil and water is caused due to the difference in surface tension of the two liquids. The water molecules stick together tightly and does not mix with the oil because water molecules are attracted to each other very strongly, forming an invisible “skin” of surface tension around each drop.
[#1227] Atomic packing factor of body centred cubic structure (bcc) is
Correct Answer
(B) 0.68
Explanation
Solution: Atomic packing factor of body centred cubic structure (bcc) is 0.68.
[#1228] A nuclear reactor is said to have become 'critical' when
Correct Answer
(D) It is ready to produce controlled energy
Explanation
Solution: To produce controlled energy i.e energy at a controlled or steady rate, the number of fissions per second must be controlled and maintained at that rate. Excess neutrons should be absorbed by control roads like cadmium.
[#1229] Nuclear reactors used to produce electricity are based on
Correct Answer
(A) Nuclear fission
Explanation
Solution: All commercial power reactors are based on nuclear fission. They generally use uranium and its product plutonium as nuclear fuel, though a thorium fuel cycle is also possible.
[#1230] The energy obtained from atoms is known as ________
Correct Answer
(C) Nuclear energy
Explanation
Solution: Nuclear energy, also called atomic energy, energy that is released in significant amounts in processes that affect atomic nuclei, the dense cores of atoms. It is distinct from the energy of other atomic phenomena such as ordinary chemical reactions, which involve only the orbital electrons of atoms.