I'd say ground. <span>Voltage in the US is 110-120 volts while in other countries it is 220-240 volts. if you have a 110-120 volt appliance, you need a step-up transformer (110 to 220)before you could use it in a 220 volt power supply.</span>
Answer:

Explanation:
Given,
Width of slit, W = 5.7 x 10⁻⁴ m
Distance between central bright fringe, L = 4 m
distance between central bright fringe and first dark fringe, y = 4 mm
Diffraction angle



Now.

m = 1



C. 10 m/s
You divide 1000 m by 100 s.
1000/100 to find the velocity