$5)$ An alpha particle is moving such that it describes a circle of radius $257\mathrm{.}8$

$$

$10$

m in a uniform

$-3$

magnetic field of strength $0\mathrm{.}040$ T$.$ The charge on an alpha particle is $3\mathrm{.}2$

$$

$10$

C and its mass is $6\mathrm{.}6$

$-19$

$$

$10$

kg$.$ What is the speed of the alpha particle?

$-27$

A$.$

$5\mathrm{.}0$

$$

$10$

m$/$s

$5$

B$.$

$4\mathrm{.}7$

$$

$10$

m$/$s

$5$

C$.$

$5\mathrm{.}2$

$$

$10$

m$/$s

$5$

D$.$

$4\mathrm{.}6$

$$

$10$

m$/$s

$5$

E$.$

$5\mathrm{.}4$

$$

$10$

m$/$s

$5$