Question

A body travelling along a straight line traversed one third of the total distance with velocity 4 m/s. The remaining part of distance was covered with a velocity 2m/s for half the time and with velocity 6 m/s for other half of time. the mean velocity averaged over whole time of motion.

Answer 1

avg. velocity for 2/3distance=(6+2)÷2=4 m/sec
net avg. velocity=4 m/sec

Answer 2

Answer:The operating principle is that – caused by the photoelectric effect – photons striking a photocathode at the entrance window of a PMT produce electrons, which are then accelerated by a high-voltage field and multiplied in number within a chain of dynodes by the process of secondary emission.

The operating principle is that – caused by the photoelectric effect – photons striking a photocathode at the entrance window of a PMT produce electrons, which are then accelerated by a high-voltage field and multiplied in number within a chain of dynodes by the process of secondary emission.

Explanation:

The operating principle is that – caused by the photoelectric effect – photons striking a photocathode at the entrance window of a PMT produce electrons, which are then accelerated by a high-voltage field and multiplied in number within a chain of dynodes by the process of secondary emission.