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प्रश्न
A proton is kept at rest. A positively charged particle is released from rest at a distance d in its field. Consider two experiments; one in which the charged particle is also a proton and in another, a positron. In the same time t, the work done on the two moving charged particles is ______.
विकल्प
same as the same force law is involved in the two experiments.
less for the case of a positron, as the positron moves away more rapidly and the force on it weakens.
more for the case of a positron, as the positron moves away a larger distance.
same as the work done by charged particle on the stationary proton.
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उत्तर
A proton is kept at rest. A positively charged particle is released from rest at a distance d in its field. Consider two experiments; one in which the charged particle is also a proton and in another, a positron. In the same time t, the work done on the two moving charged particles is more for the case of a positron, as the positron moves away a larger distance.
Explanation:
The force between two protons is equal to the force between proton and a positron because their charges are the same. As the mass of positron is much lesser than the proton, (1/1840 times) it moves away through a much larger distance compared to the proton.
Change in their momentum will be the same. So, the velocity of a lighter particle will be greater than that of a heavier particle. So, the positron is moved through a larger distance.
As work done = force x distance. As forces are the same in case of proton and positron but distance moved by positron is larger, hence, work done will be more.
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