An oil drop carrying a charge of $$2$$ electrons has a mass of $$3.2$$ × $$10$$−$$17$$kg. If is falling freely in air with terminal speed. The electric field required to make the drop move upwards with the same speed is

Question

An  oil drop carrying a charge of $$2$$ electrons has a mass of $$3.2$$   ×  $$10$$−$$17$$​kg.      If is falling freely  in air with terminal speed. The electric field required to make the drop move  upwards with the same speed is

Infinity Learn · Accepted Answer

Without electric field when oil drop is moving downwards,mg $$=$$ $$6$$ π η r υUnder el. Filed of strength E, oil drop is to move upwards∴     Fe−$$mg=6$$  π  η r υ$$=mg$$                            …$$using(i)(2$$ $$e)$$ $$E=2$$ mg        $$E=mge=3.2$$  ×  $$10$$−$$17$$×  $$101.6$$  ×  $$10$$−$$19$$            $$=2$$  ×  $$103$$ Vm−$$1$$

An oil drop carrying a charge of 2 electrons has a mass of $3.2 \times 10^{- 17} k g .$ If is falling freely in air with terminal speed. The electric field required to make the drop move upwards with the same speed is

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An oil drop carrying a charge of 2 electrons has a mass of 3.2 × 10−17​kg. If is falling freely in air with terminal speed. The electric field required to make the drop move upwards with the same speed is

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An oil drop carrying a charge of 2 electrons has a mass of $3.2 \times 10^{- 17} k g .$ If is falling freely in air with terminal speed. The electric field required to make the drop move upwards with the same speed is