Question

(i) Identify the part of the electromagnetic spectrum which is :
(a) suitable for radar system used in aircraft navigation,
(b) produced by bombarding a metal target by high speed electron.
(ii) Why does a galvanometer show a momentary deflection at the time of charging or discharging a capacitor ? Write the necessary expression to explain this observation.

Answer 1

(i) (a) Microwaves (300 Mhz - 300 Ghz)
(b) X-rays (3×10¹⁶ Hz to 3×10¹⁹ Hz)

(ii) During the charging and discharging of a capacitor, a flow of charges take place from the battery to the plates of the capacitor. This produces a conduction current in the circuit and a displacement current between plates. Hence the galvanometer shows a momentary deflection.

$\int B.dl={\mu }_{0}I+I_d$

Where $I_d=\frac{{\epsilon }_{0}d\left({\varphi }_e\right)}{dt}$