Q. The straight wire AB carries a current I. The ends of the wire subtend angles θ_{1} and θ_{2} at the point P as shown in figure. The magnetic field at the point P is

(a) $ \displaystyle \frac{\mu_0 I}{4\pi a} (sin\theta_1 – sin\theta_2)$

(b) $ \displaystyle \frac{\mu_0 I}{4\pi a} (sin\theta_1 + sin\theta_2)$

(c) $\displaystyle \frac{\mu_0 I}{4\pi a} (coos\theta_1 – cos\theta_2)$

(d) $\displaystyle \frac{\mu_0 I}{4\pi a} (coos\theta_1 + cos\theta_2)$

Ans: (a)