Light Reflection and Refraction — Class 10 Physics NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 10 Physics chapter "Light Reflection and Refraction" — 10 important questions with detailed answers for CBSE board exam preparation.
✓ 100% Free
✓ No Login Needed
✓ NCERT / CBSE Aligned
✓ Download as PDF
TL;DR: Free step-by-step NCERT solutions for Class 10 Physics chapter "Light Reflection and Refraction" — 10 important questions with detailed answers for CB…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
🤖 Stuck on any question? Ask Syllab's free AI Tutor for a step-by-step explanation — instant, unlimited, no login.
Key Questions Covered:
- Differentiate between a real image and a virtual image. State two uses of a c…
- An object is placed 20 cm in front of a concave mirror of focal length 15 cm.…
- Define the absolute refractive index of a medium. State Snell's Law of refrac…
- The refractive index of diamond is 2.42. What is the meaning of this statemen…
- Draw a neat ray diagram to show the formation of the image of an object place…
- An object 5 cm high is placed at a distance of 15 cm from a convex lens of fo…
- + 4 more questions in the full chapter
Solutions Summary:
| Question | Status |
|---|---|
| Differentiate between a real image and a virtual image. S… | ✓ Solved |
| An object is placed 20 cm in front of a concave mirror of… | ✓ Solved |
| Define the absolute refractive index of a medium. State S… | ✓ Solved |
| The refractive index of diamond is 2.42. What is the mean… | ✓ Solved |
| Draw a neat ray diagram to show the formation of the imag… | ✓ Solved |
| An object 5 cm high is placed at a distance of 15 cm from… | ✓ Solved |
Showing 6 of 10 questions
Q1: Differentiate between a real image and a virtual image. State two uses of a concave mirror.
A **real image** is formed when light rays actually converge at a point after reflection or refraction. It can be obtained on a screen. Real images are always inverted.
A **virtual image** is formed when light rays appear to diverge from a point after reflection or refraction. It cannot be obtained on a screen. Virtual images are always erect.
Two uses of a concave mirror are:
1. **Shaving mirrors:** To see a larger image of the face for a close shave.
2. **Dentists' mirrors:** To see enlarg...
Q2: An object is placed 20 cm in front of a concave mirror of focal length 15 cm. Find the position, nature, and magnification of the image.
Given:
Object distance, u = -20 cm (according to New Cartesian Sign Convention, object is always to the left)
Focal length of concave mirror, f = -15 cm (focal length of concave mirror is negative)
We use the mirror formula:
1/v + 1/u = 1/f
Substitute the given values:
1/v + 1/(-20) = 1/(-15)
1/v - 1/20 = -1/15
1/v = 1/20 - 1/15
To subtract the fractions, find a common denominator, which is 60:
1/v = (3 - 4) / 60
1/v = -1/60
v = -60 cm
The image is formed at 60 cm in front of the mirror (the...
Q3: Define the absolute refractive index of a medium. State Snell's Law of refraction. What happens to the speed of light when it passes from a rarer medium to a denser medium?
**Absolute Refractive Index (n):** It is defined as the ratio of the speed of light in vacuum (or air) to the speed of light in the given medium.
Mathematically, n = c/v, where 'c' is the speed of light in vacuum (3 x 10^8 m/s) and 'v' is the speed of light in the medium.
**Snell's Law of Refraction:** It states that for a given pair of media and for light of a given colour, the ratio of the sine of the angle of incidence (sin i) to the sine of the angle of refraction (sin r) is constant.
Mat...
Q4: The refractive index of diamond is 2.42. What is the meaning of this statement? If the speed of light in vacuum is 3 x 10^8 m/s, calculate the speed of light in diamond.
The statement 'the refractive index of diamond is 2.42' means that the speed of light in diamond is 2.42 times slower than the speed of light in vacuum (or air). In other words, light travels in vacuum 2.42 times faster than it travels in diamond.
Given:
Refractive index of diamond, n_diamond = 2.42
Speed of light in vacuum, c = 3 x 10^8 m/s
We know the formula for refractive index:
n = c / v
where v is the speed of light in the medium.
Rearranging the formula to find v:
v = c / n
v = (3 x 10...
Q5: Draw a neat ray diagram to show the formation of the image of an object placed between F and C of a concave mirror. State the characteristics of the image formed.
**Ray Diagram:**
(Imagine a diagram here with the following elements)
1. **Concave Mirror:** Draw a concave mirror with its pole (P), principal axis, principal focus (F), and centre of curvature (C).
2. **Object:** Place an object (e.g., an arrow AB) between F and C on the principal axis.
3. **Ray 1:** A ray of light from point A, parallel to the principal axis, passes through the principal focus (F) after reflection.
4. **Ray 2:** A ray of light from point A, passing through the principal f...
Q6: An object 5 cm high is placed at a distance of 15 cm from a convex lens of focal length 10 cm. Find the position, size, and nature of the image.
Given:
Object height, h_o = +5 cm
Object distance, u = -15 cm (object is placed to the left)
Focal length of convex lens, f = +10 cm (focal length of convex lens is positive)
We use the lens formula:
1/v - 1/u = 1/f
Substitute the given values:
1/v - 1/(-15) = 1/10
1/v + 1/15 = 1/10
1/v = 1/10 - 1/15
To subtract the fractions, find a common denominator, which is 30:
1/v = (3 - 2) / 30
1/v = 1/30
v = +30 cm
**Position of the image:** The positive sign for v indicates that the image is formed ...
Showing 6 of 10 questions. Visit the full page for complete solutions.