If you use your smartphone before bed, you may be interrupting your sleep. Research finds that the light wavelengths emitted by these devices may suppress sleep-inducing hormones.

Short wavelength

Explanation:

This is largely due to the short-wavelength, artificial blue light that’s emitted by these devices. The more electronic devices that a person uses in the evening, the harder it is to fall asleep or stay asleep.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .