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SS2 Physics 3rd Term Questions and Answers

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Physics Questions and Answers – SS2 – 3rd Term

Duration: 1hr 30mins

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Table of Contents – Weekly Scheme of Work

 

Section A: Objective Questions

  1. A glass prism splits white light due to:
    A. Reflection
    B. Dispersion
    C. Diffraction
    D. Scattering

  2. The angle between refracted and incident rays in a prism is the:
    A. Angle of deviation
    B. Angle of incidence
    C. Angle of emergence
    D. Apex angle

  3. A convex lens always forms:
    A. Virtual, upright image
    B. Real, inverted image (under proper conditions)
    C. No image
    D. Virtual, inverted image

  4. In a converging lens, the focal length depends on:
    A. The object color
    B. Surface curvature & refractive index
    C. The object distance
    D. The light source used

  5. A simple microscope is an example of:
    A. Camera
    B. Telescope
    C. Ophthalmoscope
    D. Convex lens used close to the eye

  6. A telescope uses lenses to:
    A. Shine lasers
    B. Collect faint distant light
    C. Make colorful images
    D. Reduce magnification

  7. What splits white light into a spectrum?
    A. Concave mirror
    B. Prism
    C. Polarizer
    D. Convex lens

  8. Dispersion causes:
    A. Light slowing down equally in glass
    B. Separation because of different refractive indices
    C. Heat only
    D. Sound

  9. Red light in prism emerges at:
    A. Larger angle than violet
    B. Same angle
    C. Smaller angle than violet
    D. No deviation at all

  10. Which colour refracts least in glass?
    A. Violet
    B. Green
    C. Red
    D. Blue

  11. Sound waves are:
    A. Transverse
    B. Electromagnetic
    C. Longitudinal
    D. Magnetic

  12. Speed of sound in air depends on:
    A. Humidity and temperature
    B. Light intensity
    C. Colour of object
    D. Air pressure only

  13. In resonance, amplitude becomes:
    A. Zero
    B. Maximum
    C. Negative
    D. Constant

  14. A tuning fork resonates at its:
    A. Chemical frequency
    B. Natural frequency
    C. Combined frequency
    D. Random value

  15. Which cannot be seen in Newton’s Rings?
    A. Concentric rings
    B. Alternating dark/bright bands
    C. Varying radii
    D. Uniform dark field

  16. Lens power is defined by:
    A. 1/f (f in metres)
    B. F × 2
    C. f²
    D. f × 100

  17. Myopia correction uses:
    A. Convex lens
    B. Concave lens
    C. Prism
    D. Plane glass

  18. Dispersion correct uses:
    A. Water
    B. Polarizer
    C. Lens combination
    D. Mirrors

  19. Incident ray enters prism at 45°, emerges deviated by 60°. Apex is 30°. Angle of emergence is:
    A. 30°
    B. 45°
    C. 15°
    D. 75°

  20. For a thin lens formula 1/f = 1/u + 1/v, u is:
    A. Focal length
    B. Image distance
    C. Object distance
    D. Thickness

  21. Telescope resolution improved by:
    A. Increasing aperture
    B. Lengthening eyepiece only
    C. Changing eyepiece colour
    D. Cooling the lenses

  22. Concave lens always forms:
    A. Real inverted image
    B. Virtual upright image
    C. No image
    D. Real upright image

  23. Image in magnifying glass is:
    A. Real, enlarged
    B. Virtual, enlarged
    C. Virtual, same size
    D. Real, same size

  24. Dispersion arises due to:
    A. Same refractive index
    B. Different refractive index for each colour
    C. Constant speed in glass
    D. Energy loss

  25. Vibration causing resonance needs to match:
    A. Any frequency
    B. Natural frequency of object
    C. Double natural frequency
    D. Electromagnetic frequency

  26. Sound waves do not travel in:
    A. Vacuum
    B. Solid
    C. Liquid
    D. Gas

  27. Loudness perceived depends on:
    A. Wavelength
    B. Frequency
    C. Amplitude
    D. Pitch

  28. Pitch depends on:
    A. Wave amplitude
    B. Frequency
    C. Medium only
    D. Temperature

  29. In optical instrument, lenses are used to:
    A. Bend light for magnification or focusing
    B. Generate electricity
    C. Produce sound
    D. Block dust

  30. Dispersion is reversed by:
    A. Single convex lens
    B. Second prism inverted
    C. Concave mirror
    D. Grating

  31. Refraction at surface is described by:
    A. Newton’s 1st law
    B. Snell’s law
    C. Pythagoras’ theorem
    D. Ohm’s Law

  32. Critical angle arises when refracted ray travels:
    A. Normal
    B. Along boundary
    C. Away from interface
    D. At 90°

  33. TIR occurs when incident angle is:
    A. Less than critical
    B. Equal to Snell’s limit
    C. Greater than critical
    D. Zero

  34. Speed of sound in solids is:
    A. Less than in air
    B. Greater than in air
    C. Same as water
    D. Zero

  35. Beats occur due to interference of:
    A. Two sounds of slightly different freqs
    B. Sound and light
    C. Two identical frequencies
    D. Light interference

  36. Node in standing wave is a point of:
    A. Maximum amplitude
    B. Minimum amplitude
    C. Zero motion
    D. Vibration transfer

  37. Antinode has:
    A. No vibration
    B. Maximum vibration
    C. Constant vibration
    D. Vibration zero

  38. Lenses in camera act as:
    A. Concave only
    B. Convex only
    C. Plane glass
    D. Prism

  39. Colour separation in soap film is due to:
    A. Dispersion only
    B. Thin-film interference
    C. Diffraction only
    D. Sound waves

  40. Echo occurs due to:
    A. Dispersion
    B. Reflection of sound
    C. Refraction of sound
    D. Diffraction

 

Section B: Theory Questions

  1. Glass prism
    Explain dispersion of light in a glass prism. Derive the expression for angle of deviation in a thin prism.

  2. Lenses
    A converging lens forms an image 15 cm from lens for an object 10 cm away. Calculate focal length and magnification.

  3. Microscope
    Describe the construction and working of a compound microscope. How does changing the eyepiece affect magnification?

  4. Telescope
    Compare astronomical and terrestrial telescopes, including lenses used and image orientation.

  5. Dispersion
    Why does violet light deviate more than red in glass? Explain using wave-particle and refractive index perspective.

  6. Sound wave properties
    Derive formula for the speed of sound in air using kinetic theory or Newton-Laplace equation.

  7. Resonance
    Explain resonance in air columns. Describe experiment to find the speed of sound using resonance tube.

  8. Critical angle and total internal reflection
    Derive critical angle for air-glass interface. Give two real-life applications.

  9. Beats and interference
    Explain formation of beats when two waves of nearly equal frequency superpose. Derive formula for beat frequency.

  10. Doppler effect
    Derive the expression for frequency shift when source approaches a stationary observer. Give real-world example.

Section C: Theory Questions

  1. Glass prism
    Explain dispersion of light in a glass prism. Derive the expression for angle of deviation in a thin prism.

  2. Lenses
    A converging lens forms an image 15 cm from lens for an object 10 cm away. Calculate focal length and magnification.

  3. Microscope
    Describe the construction and working of a compound microscope. How does changing the eyepiece affect magnification?

  4. Telescope
    Compare astronomical and terrestrial telescopes, including lenses used and image orientation.

  5. Dispersion
    Why does violet light deviate more than red in glass? Explain using wave-particle and refractive index perspective.

 

Section D: Theory Answers

Glass Prism

Dispersion:
When white light enters a glass prism, it splits into its constituent colors. This occurs because each wavelength is refracted by a different amount violet bends the most and red bends the least due to their different refractive indices.

Deviation Derivation (Thin Prism Approximation):

For a thin prism of apex A and small angles, total deviation δ≈(μ−1)A, where μ is the refractive index.

2. Lenses

Given u=10u, v=15v.
Use thin lens formula:

   1/f = 1/u + 1/v = 1/10 + 1/15 = 1.5+1/15 = 2.5/15 = 1/6

Magnification:

So, f=6cm

Magnification m=v/u=15/10=1.5.

3. Microscope

Construction:
Two lenses objective and eyepiece are aligned coaxially.

Working:
The objective lens forms a real, inverted, magnified image just outside its focal point. This image serves as the object for the eyepiece, which acts as a magnifier.

Eyepiece effect:Using a shorter focal length eyepiece increases total magnification but narrows field of view.

4. Telescope

Comparison:
Terrestrial telescopes are more complex but produce upright images, making them suitable for Earth-based use.

5. Dispersion of White Light

Why violet deviates most:
Glass has a higher refractive index for shorter wavelengths (violet), which leads to greater slowing and more refraction.

Wave-particle view:
Shorter wavelengths interact more with the glass molecules, causing them to bend more.

Conclusion

Revise all topics from Weeks 1–9 thoroughly optics and sound are core to SS2 Physics. Practice both objective and theory questions for deeper mastery. Stay consistent, maintain academic integrity, and approach your exams with confidence and discipline.

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