A Level Physics Practice Exam

The correct formula for calculating the wavelength in the diffraction grating equation is derived from the fundamental relationship that relates the distance between adjacent slits (d), the angle of diffraction (X), and the order of the spectrum (n) to the wavelength. This relationship is expressed as: d * sin(X) = n * λ In this formula, λ represents the wavelength of the light. The equation states that the product of the slit separation (d) and the sine of the angle of diffraction (sin(X)) is equal to the order of the spectrum (n) multiplied by the wavelength (λ). This relationship is crucial in understanding how light diffracts when passing through a grating, leading to the formation of distinct interference patterns based on the wavelength of the light. The choice accurately presents the formula that illustrates this physical phenomenon. The other options misrepresent the relationship by rearranging the variables incorrectly or suggesting relationships that do not conform to the physics of diffraction gratings.