MCQ (Solution) - Light: Mirrors and Lenses | Science Curiosity Class 8 - New NCERT PDF Download

Answer: Option B
Solution:

• A concave mirror has an inward-curving reflecting surface; a convex mirror has an outward-curving reflecting surface.
• Concave mirrors can produce inverted images when the object is sufficiently far; convex mirrors never produce inverted images for real objects.
• Why others are incorrect: A swaps definitions; C confuses spherical with plane mirrors; D is false—concave mirrors do invert for larger object distances.

Answer: Option A
Solution:

• Convex mirrors always give erect, diminished images and cover a larger area, hence the safety warning “Objects in mirror are closer than they appear.”
• Why others are incorrect: B and C contradict convex mirror image nature; D confuses with plane mirrors and ignores wide field of view.

Answer: Option A
Solution:

• Near a concave mirror, the image is erect and magnified; farther away, the image becomes inverted (initially enlarged, then diminishing with distance).
• Why others are incorrect: B describes convex mirror behavior; C and D ignore distance-dependent image changes for concave mirrors.

Answer: Option C
Solution:

• Concave reflectors converge light into a beam (torch/headlights); convex mirrors are used for wide-angle viewing (side-view mirrors, intersection mirrors).
• Dentists use concave mirrors to get enlarged, close-up views.
• Why others are incorrect: A: dentist needs concave; B: safety mirror is convex; D: vehicles use convex, not concave.

Answer: Option A
Solution:

• Law 1: ∠i = ∠r for any reflecting surface (plane or spherical), measured from the normal at the point of incidence.
• Why others are incorrect: B is meaningless; C is not general; D is false—laws hold for all mirrors.

Answer: Option B
Solution:

• Law 2: The incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane.
• Why others are incorrect: A contradicts the law; C and D are special/impossible cases, not the general rule.

Answer: Option B
Solution:

• Concave mirrors converge parallel incident rays; convex mirrors cause divergence; plane mirrors keep them parallel.
• Why others are incorrect: A applies to plane mirrors; C applies to convex; D is unphysical.

Answer: Option A
Solution:

• For close objects, a convex lens acts as a magnifier producing an erect, enlarged image (basis of magnifying glasses and reading lenses).
• Farther objects may produce inverted images whose size varies with distance.
• Why others are incorrect: B and D occur for certain object distances but inverted is not for close viewing; C describes concave lens behavior.

Answer: Option A
Solution:

• Concave lenses are diverging; they always produce virtual, erect, and diminished images of real objects.
• Why others are incorrect: B and C contradict the diverging nature; D is false—images exist (virtual).

Answer: Option B
Solution:

• Concave mirrors and convex lenses can concentrate parallel sun rays to a small area, raising temperature enough to char or ignite paper (principle of solar concentrators).
• Why others are incorrect: A, C, D do not describe the optical focusing mechanism.

Answer: Option B
Solution:

• A thin flat window simply transmits light without magnification; a convex lens can produce an erect, enlarged image for close viewing.
• Why others are incorrect: A reverses; C and D are false in general use.

Answer: Option B
Solution:

• Parallel rays reflect to converge for concave mirrors; remain parallel for plane mirrors; diverge for convex mirrors; concave lenses diverge transmitted rays.
• Why others are incorrect: A, C, D mismatch observed beam behavior.

Answer: Option A
Solution:

• Incidence along the normal implies ∠i=0°, so ∠r=0°; the ray retraces its path.
• Why others are incorrect: B misstates the angle; C is not general; D contradicts the reflective behavior.

Answer: Option B
Solution:

• Convex curvature lets more peripheral rays reflect towards the observer, showing a wider scene (basis for use in vehicles and safety mirrors).
• Why others are incorrect: A is false (they diminish); C describes concave focusing; D is opposite of wider view.

Answer: Option B
Solution:

• A concave (diverging) lens always produces erect, diminished, virtual images of real objects; a convex lens can produce erect enlarged (near) or inverted images (far), so its behavior varies with distance.
• Why others are incorrect: A and C wrongly claim “always” for convex; D is contrary to concave lens behavior.