Question

1 pre board science class 10 sample paper

Answer 1

MULTIPLE CHOICE QUESTIONS BASED ON EXPERIMENT: To determine the focal length of a concave mirror by obtaining the image of a distant object
A spherical mirror to be made from a cut portion of
(a) hollow sphere of glass (b) solid sphere of plastic
(c) solid sphere of glass (d) hollow sphere of metal
2. The relation between focal length f and radius of curvature R for a spherical mirror is
(a) f = 2R (b) f = R/2
(c ) f = R/4 (d) f =2R
The image formed by a concave mirror is virtual and erect & on the same side of the object. The position of the object is
(a) at center of curvature (b) at the principle focus
(c) between F and C (d) between P & F
To determine the focal length of a concave mirror by forming image of a distant object, the screen should be placed
(a) in any direction (b) inclined at an angle of 45
(c) at right angle to the plane of the mirror (d) Parallel to the plane of mirror
An object is placed at a distance of 20cm in front of concave mirror of focal length 10cm. The image produced is
(a) real, inverted & diminished (b) real, inverted & enlarged
(c) real inverted & same size (d) virtual, erect and enlarged
In order to determine focal length of a concave mirror by obtaining the image of distant object on screen you need to measure the distance between
(a) mirror and the screen (b) object & screen
(c) mirror & object (d) mirror & screen also between object and screen
For a plane mirror, the value of focal length is
(a) anything between zero & infinity (b) infinity
(c) zero (d) f = R
For spherical mirror, all the distances are measured from
(a) principle focus of the mirror (b) center of curvature of the mirror
(c) either pole or center of curvature (d) pole of the mirror
A parallel beam of light coming from the distant object incident on a concave mirror parallel to its principal axis. After reflection from the mirror, the beam
(a) passes through its principal focus (b) appears to pass through its principal focus
(c) appears to reflect from the point of (d) appears to pass through its center of
incidence curvature
As per sign convention , the focal length of a concave mirror is
(a) negative (b) positive
(c) not certain (d) positive or negative
11. Is focal length of a spherical mirror fixed, what ever be the position of the object?
(a) yes, sometimes (b) No, never
(c) No, sometimes (d) yes, always

ANSWERS:

1. (a) 2. (b) 3. (d) 4. (d) 5. (c) 6. (a) 7. (b) 8. (d) 9. (a) 10. (a) 11. (d)