Exams › JEE Main › Physics

A light wave moving through vacuum has wavefronts described by the equation x + y + z = c. What angle does the propagation direction of the light make with the X-axis?

1. 0°
2. 45°
3. 90°
4. cos⁻¹(1/√3)

Correct answer: cos⁻¹(1/√3)

Solution

The equation of the wavefront indicates that the wave is propagating equally in the x, y, and z directions, which corresponds to a direction vector of (1, 1, 1). The angle with the X-axis can be calculated using the cosine of the angle, which gives cos(θ) = 1/√3, leading to the correct answer.

Related JEE Main Physics questions

• The pupil opening of a human eye is about 2 mm. If the average wavelength of visible light is taken as 5000 Å, the eye’s approximate angular resolving limit is
• For a single-slit diffraction pattern, the condition corresponding to the appearance of secondary maxima is
• In a Fresnel biprism setup, the two lens positions give slit separations of 16 cm and 9 cm. What is the true separation between the slits?
• In a Young’s double-slit setup, two monochromatic sources emit light of wavelengths 2500 Å and 3500 Å. Which pair of fringe orders from the two patterns will fall at the same position?
• In a Young’s double-slit setup, the intensity at a bright fringe maximum is I0. The slit separation is d = 5bb, where bb is the wavelength of the light used. If the screen is placed at a distance D = 10d, what intensity is observed at the point directly opposite one of the slits?
• What is the relationship between the polarizing angle and the critical angle?

⚔️ Practice JEE Main Physics free + battle 1v1 →