Mirror, Mirror
What kind of image does a plane mirror always form?
Virtual and erect
A convex lens is also called a _____ lens.
Answer: Converging
What is the angle between the reflected ray and the normal called?
Answer: Angle of reflection
In which direction does a ray pass through the focus in a concave mirror diagram?
Answer: Parallel to principal axis after reflection
What is the mirror formula?
Answer: 1/f = 1/v + 1/u
What is the nature of image formed by a convex mirror?
Answer: Virtual, erect, diminished
What is the sign of focal length for a concave lens?
Answer: Negative
State the law of reflection.
Answer: Angle of incidence = angle of reflection
I,N,R lies on the same side of the plane
How do rays behave when they pass through the optical center of a lens?
Answer: They go undeviated
An object is placed 20 cm from a concave mirror. Focal length is 10 cm. Find the image distance.
Answer: v = -20 cm
A concave mirror forms a real and inverted image. Where is the object placed?
Answer: Beyond the center of curvature
Name one device that uses a convex lens to converge light.
Answer: Magnifying glass/camera lens
Why does a pencil appear bent in water?
Answer: Due to refraction of light
Where is the image formed when an object is placed at F in front of a convex lens?
Answer: At infinity
A 3 cm tall object is 25 cm from a concave lens of focal length 15 cm. Find the image distance, height and nature of the image.
v ≈ –9.38 cm; hᵢ ≈ +1.13 cm (virtual, upright, diminished).
A shaving mirror gives a magnified, erect image. What kind of mirror is it and how close must the object be?
Answer: Concave mirror, placed between pole and focus
What type of image is formed by a concave lens, irrespective of object position?
Answer: Virtual, erect, diminished
What is the refractive index of water if the speed of light in vacuum is 3x10^8 m/s and in water is 2.25x10^8 m/s?
Answer: 1.33
Draw a ray diagram for an object placed between F and pole of a concave mirror.
Answer: Virtual, erect, magnified
An object 5 cm high is placed 15 cm from a lens with focal length 10 cm. Find magnification.
Answer: m = 2
What happens to the image in a concave mirror as the object moves from infinity to the focus?
Answer: The image moves from focus to infinity, becomes smaller to larger, real to virtual
If a real, inverted image is twice the size of the object, where is the object placed in front of a convex lens?
Answer: Between F and 2F
Name the phenomenon responsible for the formation of a rainbow.
Answer: Dispersion, refraction, and reflection
Where will be the image formed when an object is placed at a distance of 20 cm of a concave mirror whose focal length is 20 cm. Also mention the size and nature of an image
Infinity, Real Inverted and magnified
A 4 cm tall object is 20 cm from a convex lens of focal length 10 cm. Find the image distance and height.
v = +20 cm; hᵢ = –4 cm (real, inverted, same size).