Question

The number of electric lines of force originating from a charge of 1 C is
(a) 1.129 × 10¹¹
(b) 1.6 × 10⁻¹⁹
(c) 6.25 × 10¹⁸
(d) 8.85 × 10¹²

Answer 1

Electric lines of force is an imaginary continuous lines or curve in such a way that tangent at any point on it always gives direction of electric field.
According to definition , it is clear that electric lines of force is an imaginary line or curve . Higher the density of electric lines of force , higher will be intensity and vice-versa .

Basically number of electrons shows number of electric lines of forces because we assume smallest charge originating from any particle is electronic charge. e.g., 1e = 1.6 × 10⁻¹⁹C

Let's find how much electric lines of force is originating from1 C charged particle.
number of electrons = n
charge on each electrons = 1.6 × 10⁻¹⁹C
so, Q = ne
⇒ 1 = n × 1.6 × 10⁻¹⁹
n = 10¹⁹/1.6 = 6.25 × 10¹⁸
∵ number of electrons = 6.25 × 10¹⁸
∴ number of electric lines of force = 6.25 × 10¹⁸

Hence, option (c) is correct