Class 10, Science, Chapter-9, Lecture-2, Spherical Mirror (Notes)
CHARACTERISTICS OF AN IMAGE FORMED BY A CONCAVE MIRROR:
POSITION OF OBJECT | CHARACTERISTICS OF IMAGE | RAY DIAGRAM |
---|---|---|
At Infinity | At focus Real and Inverted Highly diminished | FIGURE 10.7 (a) OF NCERT TEXT BOOK |
Beyond ‘ C ’ | Between F and C Real and Inverted Diminished | FIGURE 10.7 (b) OF NCERT TEXT BOOK |
At ‘ C ’ | At C Real and Inverted Of Same size | FIGURE 10.7 (c) OF NCERT TEXT BOOK |
Between F and C | Beyond C Real and Inverted Magnified | FIGURE 10.7 (d) OF NCERT TEXT BOOK |
At ‘ F ’ | At Infinity Real and Inverted Highly magnified | FIGURE 10.7 (e) OF NCERT TEXT BOOK |
Between F and P | Behind the mirror Virtual and Erect Magnified | FIGURE 10.7 (f) OF NCERT TEXT BOOK |
CHARACTERISTICS OF AN IMAGE FORMED BY A CONVEX MIRROR:
POSITION OF OBJECT | CHARACTERISTICS OF IMAGE | RAY DIAGRAM |
---|---|---|
At Infinity | At focus (behind the mirror) Virtual and Erect Highly diminished | FIGURE 10.8 (a) OF NCERT TEXT BOOK |
Between Infinity and the Pole of the mirror | Between F and P (behind the mirror) Virtual and Erect Diminished | FIGURE 10.8 (b) OF NCERT TEXT BOOK |
USES OF SPHERICAL MIRRORS:
Concave Mirrors:
- as reflectors in the headlights of cars.
- as the Doctor’s mirror to focus light on the region to be examined.
- as shaving mirrors and make-up mirrors.
- as radiation collector in solar heating devices.
Convex Mirrors:
- as rear-view mirrors or side-mirror of cars, trucks and buses.
- as vigilance-mirrors in big shops and stores.
Reasons:
- A convex mirror always produces an erect image.
- The surface of a convex mirror is curved outwards which provides a wider field of view.
SIGN CONVENTION FOR SPHERICAL MIRRORS:
- Light is incident on the mirror from the left-hand side of the mirror.
- All distances are measured from the pole (P).
- Distances in the direction of incident ray are taken as positive.
- Distances against the direction of incident ray are taken as negative.
- Distances measured upward and perpendicular to the principal axis are taken as positive.
- Distances measured downward and perpendicular to the principal axis are taken as negative.