Question

Consider an experiment done in a ripple tank with plane waves incident on a barrier with two slits separated by a distance of 1.10 cm. The waves pass through a plane parallel to the barrier, 2.31 m from the slits. If the phase speed of water waves in the tank is 0.029 m/s and an oscillator produces waves with a frequency of 7.23 Hz, how far from the center of the plane will the second order maxima be found? Drawing a diagram will help you to visualize the situation. (ans. 2.46 m)

9. A laser beam of unknown wavelength passes through a double slit with separation 2.50 µm. The third intensity minimum (m = 2) is found at an angle of 29.2°. What is the wavelength of the laser beam? (ans. 488 nm)

10. Light of two wavelengths, 575 nm and 675 nm, is incident on a diffraction grating with 88 lines per millimetre. What are the angles of the third-order maxima produced by these wavelengths of light? (ans. 8.73 deg, 10.26 deg)

11. Visible light passes through a diffraction grating with 900 slits per centimetre. The interference pattern is observed on a screen 2.50 m from the grating. In the first-order spectrum on the screen, maxima for two different wavelengths are 24.9 mm apart. What is the difference between the two wavelengths, Δλ? [ans. 110 nm]

Answer 1