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Answer: B. I only (I true; II false, yellow deviated less than green; III false, rainbows from light refraction in drops.)

Answer: A n = \(\frac{1}{\text{sinC}}\) = \(\frac{1}{sin45º}\) = \(\sqrt{2}\).

\(_ag_g\) = \(\frac{\text{sini}}{\text{sinr}}\) sinr = \(\frac{\text{sini}}{_ag_g}\) sinr = \(\frac{0.5}{1.5}\) sinr = 0.3

A. Red Red light has the longest wavelength and the lowest frequency compared to the other colors listed. ROYGBIV: arranged in increasing frequency or decreasing wavelength.

For a ray entering and exiting parallel faces of a glass slab, the refractive index is given by: n = \(\frac{\text{real depth}}{\text{apparent depth}}\) Where SR = 6cm is apparent depth, SQ = 10cm real depth. n = \(\frac{10}{6}\) = 1.6666 ≈ 1.67

i at m\(_1\) = 60^\circ → r = 60^\circ at m\(_1\) (law of reflection i ^\circ = r ^\circ) i at m\(_2\) = 30^\circ i = r, ∴ r = 30^\circ

\(\lambda\) = \(\frac{\text{Sin i}}{\text{Sin r}}\) = \(\frac{Sin 60º}{Sin 32º}\) = 1.63

For all positions of the object formed by a concave (diverging) lens, the image is virtual, erect, and diminished.

2a. Table of observations D(cm) D\(^2\)(cm\^2\) X\(_1\)(cm) L = (X\(_1 - X_2\)) L\(^2\)(cm\(^2\)) 100 10000 80.50 62.20 3868.8 90 8100 70.20 51.20 2621.4 80 6400 59.10 39.10 1528.8 70 4900 46.70 24.70 610.09 60 3600 29.00 21.40 457.96 S = \(\frac{y_2 - y_1}{x_2 - x_1}\) = \(\frac{6250 - 3250}{100 - 60}\) = \(\frac{3000}{40}\) = 75 K = \(\frac{\text{s}}{4}\) = \(\frac{75}{4}\) = 18.75 Precautions: (i) I carefully avoided parallax error by ensuring my eyes were directly in line with the markings on the metre rule while taking measurements to improve accuracy. (ii) I adjusted the setup and focused precisely to ensure a sharp and well-defined image was formed on the screen, minimizing errors due to blurriness or misalignment. (iii) I made sure that the experimental apparatus was stable and free from vibrations to avoid any disturbance during measurements. (iv) I ensured that the metre rule was properly calibrated and positioned perpendicular to the setup to prevent measurement inaccuracies due to angle errors. bi. A real image is formed when light rays converge and meet at a point, allowing it to be projected onto a screen. It is typically inverted relative to the object, as seen in concave mirrors or convex lenses when the object is beyond the focal point. On the other hand, a virtual image is formed when light rays appear to diverge from a point but do not actually meet. This type of image cannot be projected onto a screen and is always upright, as seen in plane mirrors or convex mirrors. bii. See diagram above.

The distance between two successive troughs of a wave is equal to one wavelength (\lambda) One wavelength (\lambda) is defined as the distance between two successive points in the same phase (crest to crest or trough to trough).

f = \(\frac{\text{no of oscillation made}}{t(s)}\) = \(\frac{60}{4}\) = 15 Hz This distance equals 2 wavelengths (because there are 3 troughs, each with 2 intervals between them). 2\(\lambda\) = 15 \(\lambda\) = \(\frac{15}{2}\) = 7.5m V = f\(\lambda\) v = 15 \times 7.5 = 112.5 ms\(^{-1}\)

Polarisation only occurs with a wave whose direction is perpendicular to its vibration (i.e., transverse waves)

T = 0.02 s; \lambda = ?; v = 330 ms⁻¹; f = \(\frac{1}{\text{T}}\) = \(\frac{1}{0.02}\) = 50 Hz But; v = f\lambda \lambda = \(\frac{\text{v}}{\text{f}}\) = \(\frac{330}{50}\) = 6.6 m

The speed of sound in air at a constant temperature is primarily dependent on the temperature of the air rather than the pressure. At a constant temperature, changes in pressure do not significantly affect the speed of sound.

Speed of sound = 60 m/s Time delay = 4 s (light travel time is negligible) Distance = speed \times time = 60 \times 4 = 240 m