Telangana 10th Class Imp Questions

Following are the important 4 Marks Questions for SSC / 10th Class public exams for AP and Telangana students as per CCE pattern of syllabus. These questions are from the chapter of Physical Sciences, Reflection of Light at Curved Surfaces:

Q: List the materials required for conducting an experiment to find the focal length of a concave mirror. Explain the experimental process also.
A: Materials required: 1) Concave mirror 2) Candle 3) Paper screen 4) v-stand 5) Meter Scale

Procedure:

Place the concave mirror on v-stand, a candle, paper screen and meter scale as shown in the figure.

Put the candle at different distances from the mirror along the scale and by moving the screen find the position where the sharp
image is formed on the paper screen.

In each case note the distance (u) of the candle from the mirror and the respective screen distance (v) from the mirror

Tabulate the observations.

Find the average of focal lengths (f) obtained.
This average value of focal length (f) is the focal length of the concave mirror.

Part – B

I. Choose the correct answer:

1. An object is placed at 5 cm distance in front of a concave mirror of 6 cm focal length, then the nature of the image is
A) Real and inverted B) Virtual and erect
C) Virtual and inverted D) Real and erect

2. Sita is searching for light of parallel beam.
This source can help her….
A) Torch B) Candle C) Sun D) Sodium vapour lamp

3. The shape of solar cooker is
A) Concave B) Plane C) Ellipsoid D) Convex

Answers:

1-B, 2-C, 3-A.

Following are important questions of 1 mark and 2 marks from the chapter Reflection of Curved Surfaces of 10th Class Physical Sciences. The questions are given for the public examinations and useful for AP and Telangana SSC board exams.

1 Mark Questions

Q: Which property of a concave mirror helps the dentists to check the dental problems?
A: When an object is held close to the concave mirror (less than its focal length), its enlarged erect image will be formed in the
mirror. This property is used by dentists to check the dental problems.

Q: Your friend noted the measurements of object distance and image distance in an experiment with a concave mirror and made a conclusion. What would be his conclusion?
A: He might have concluded that the focal uv length of the concave mirror is f = uv / u+v. Here u is the object distance and v is the
image distance from the concave mirror.

Q: If the focal length of a concave mirror is 20 cm, find the radius of curvature of that mirror?
A: Formula: Radius of curvature R = 2f. Given: focal length f = 20 cm; ∴ Radius of curvature R = 2f = 2 × 20 = 40 cm

Q: Which type of device do you use to see objects at the rear to your vehicle?
A: I use convex mirror to see the rear objects of the vehicle.

2 Marks Questions:

Q: Which objects at your home work as spherical mirrors?
A: The outer surface of stainless steel utensils, spoons, plates work as convex mirrors. The inner surfaces of the above said objects work as concave mirrors.

Q: Write any four differences between types of images formed by a concave mirror.
A: Two types of images are formed by a concave mirror. They are
1) Real image and
2) Virtual image.

Real image:

1) Real image can be caught on a screen.
2) The image may be enlarged, diminished or same size of the object.
3) Real image is always inverted.
4) Real image is formed when the reflected rays are converged.

Virtual image:

1) Virtual image can not be caught on a screen.
2) Virtual image is always enlarged.
3) Virtual image is always erect.
4) Virtual image is formed when the reflected rays are diverged.

Q: Hold a concave mirror such that sun light falls on it. What happens if you hold the paper at a distance shorter than the focal
length from the mirror and move it away.
A: We notice that the image of the sun on the paper first becomes blurred as the paper is kept at a distance shorter than the focal
length of the mirror.

“As the paper moves to the focus of the concave mirror, the image becomes sharp and small”.
”As the paper moves away from focus the image becomes bigger in size”.