The potential difference applied to an X-ray tube is 5 KV and the current through it is 3.2 mA. Then the number of electrons striking the target per second is

A beam of electrons moving at a speed of 10⁶ m/s along a line produces a current of 1.6 × 10^–6 A. The number of electrons in the 1 metre of the beam is

In the Bohr’s model of hydrogen atom, the electrons moves around the nucleus in a circular orbit of a radius 5 × 10^–11 metre. It’s time period is 1.5 × 10^–16 sec. The current associated is

An electron is moving in a circular path of radius 5.1 × 10^–11 m at a frequency of 6.8 × 10¹⁵ revolution/sec. The equivalent current is approximately

A copper wire of length 1m and radius 1mm is joined in series with an iron wire of length 2m and radius 3mm and a current is passed through the wire. The ratio of current densities in the copper and iron wire is

A conducting wire of cross-sectional area 1 cm² has 3 × 10²³ m^–3 charge carriers. If wire carries a current of 24 mA, the drift speed of the carrier is

A wire has a non-uniform cross-sectional area as shown in figure. A steady current i flows through it. Which one of the following statement is correct

In a wire of circular cross-section with radius r, free electrons travel with a drift velocity v, when a current i flows through the wire. What is the current in another wire of half the radius and of the some material when the drift velocity is 2v

A potential difference of V is applied at the ends of a copper wire of length l and diameter d. On doubling only d, drift velocity

A current flows in a wire of circular cross-section with the free electrons travelling with a mean drift velocity v. If an equal current flows in a wire of twice the radius new mean drift velocity is