In Newton's Ring experiment the ratio of the wavelength of light used from two monochromatic sources is 1:4. If the diameter of the 10th dark ring obtains from the first source is 0.5 cm. Then the diameter of the 10th dark ring by using sound source is.
1
0.1 cm.
2
0.5 cm.
3
0.8 cm.
4
1 cm.