Adiffraction grating is illuminated simultaneously with red light of wavelength 660 {\rm nm} and light of an unknown wavelength. the fifth-order maximum of the unknown wavelength exactly overlaps the third-order maximum of the red light. what is the unknown wavelength? (in nm)

Explanation:

As we know that position of maximum on the screen in diffraction pattern is given as

here we know that

position of third maximum due to red color light and position of fifth maximum of unknown wavelength are same

so we have

so we have

unbalanced force

explanation:

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27