An ion flies into a uniform magnetic field with an induction of 87 mT perpendicular to the

An ion flies into a uniform magnetic field with an induction of 87 mT perpendicular to the induction lines. The ion velocity is 50 km / s, the charge is 3.2 ˑ 10 (-19) C, the radius of its trajectory is 12 cm. What is the mass of the ion?

Let’s write the formula for solving the problem:
F = q * v * B * sin a, we know that sin a = sin 90 = 1;
Let’s transform the formula:
F = m * a,
The formula for finding a:
a = v ^ 2 / R;
Now let’s combine the formulas:
q * v * B = m * v ^ 2 / R;
Let’s transform again:
m = q * B * R / v;
Substitute the value formula and solve:
m = (3.2 * 10 ^ -19 * 87 * 10 ^ -3 * 0.12) / (5 * 10 ^ 4);
m = 6.7 * 10 ^ -26 kg;
Answer: m = 6.7 * 10 ^ -26 kg.