Answer:
1.2826 x 10^-13 m
Explanation:

Here, k be the kinetic energy and m be the mass
K = 50 KeV = 50 x 1.6 x 10^-16 J = 80 x 10^-16 J
m = 1.67 x 10^-27 kg

λ = 1.2826 x 10^-13 m
Complete Question:
In the same configuration of the previous problem 3, four long straight wires are perpendicular to the page, and their cross sections form a square of edge length a = 13.5 cm. Each wire carries 7.50 A, and the currents are out of the page in wires 1 and 4 and into the page in wires 2 and 3.
a) Draw a diagram in a (x,y) plane of the four wires with wire 4 perpendicular to the origin. Indicate the current's directions.
b) Draw a diagram of all magnetic fields produced at the position of wire 3 by the other three currents.
c) Draw a diagram of all magnetic forces produced at the position of wire 3 by the other three currents.
d) What are magnitude and direction of the net magnetic force per meter of wire length on wire 3?
Answer:
force, 1.318 ₓ 10⁻⁴
direction, 18.435°
Explanation:
The attached file gives a breakdown step by step solution to the questions
T² caries directly as R³ .
This is Kepler's 3rd law of planetary motion .