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D. 1.25 m In a pinhole camera, the relationship between image size and object size is given by: \(\frac{\text{Image Size}}{\text{Object Size}} = \frac{v}{u}\) where \( v \) is the camera length. Given \( v = 25 \, \text{cm} = 0.25 \, \text{m} \). The image is one-fifth the object size, so the magnification is: \(\text{Magnification} = \frac{1}{5} = \frac{v}{u}\) Thus, we can rearrange this to find \( u \): \(u = 5v = 5 \times 0.25 = 1.25 \, \text{m}\).

In a kaleidoscope (two plane mirrors inclined at an angle ( \theta )): \(\text{Number of images of one object} = \frac{360^\circ}{\theta} - 1\) Given: \(\theta = 30^\circ\) \(\frac{360}{30}\) = 12 So, images formed by one object: 12 - 1 = 11 For 10 objects (tinsels): 10 x 11 = 110 images formed.

Annular Eclipse: Occurs when the Sun, Moon, and Earth are aligned in a straight line, but the Moon is at a distance where it does not completely cover the Sun.

Pinhole camera, shadow formation, and the occurrence of an eclipse are a result of the rectilinear propagation of light.

The moon is not self-luminous. Self-luminous objects are those that can emit light on their own. The moon does not emit light; it only reflects light from the sun.

When the object is placed exactly at the centre of curvature, the image forms at the same location (centre of curvature), real, inverted, and the same size.

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.