Spherical Lenses

The video explores the evolution and significance of optical instruments, focusing on spherical lenses. It details the types of lenses, such as convex and concave, and their properties, including refraction and focal length. The video explains ray diagrams, sign conventions, and how lenses form images at various object positions. It concludes with a summary of spherical lenses' characteristics.

What was the original use of the burning glass in ancient times?

• To magnify tiny objects

• To produce fire

• To create optical illusions

• To measure distances

Which type of lens has two convex surfaces?

• Plano-concave

• Concavo-convex

• Biconvex

• Plano-convex

What is the principal focus of a convex lens?

• The point where rays parallel to the principal axis converge

• The point where rays parallel to the principal axis diverge

• The center of the lens

• The midpoint of the lens

What happens to light rays when they pass through the optical center of a thin lens?

• They pass undeviated

• They diverge

• They converge

• They reflect

What is the relationship between the radius of curvature and the focal length of a lens?

• The radius of curvature is unrelated to the focal length

• The radius of curvature is equal to the focal length

• The radius of curvature is twice the focal length

• The radius of curvature is half the focal length

According to the New Cartesian Sign Convention, what is the sign of the focal length for concave lenses?

• Positive

• Negative

• Zero

• Undefined

What type of image is formed by a convex lens when the object is at 2F1?

• Virtual, erect, and magnified

• Real, inverted, and of the same size

• Real, inverted, and diminished

• Virtual, erect, and diminished

How can a clear ice block be used to start a fire?

• By shaping it into a concave lens

• By shaping it into a convex lens

• By using it as a mirror

• By melting it to focus sunlight

What type of image does a concave lens always form?

• Real, erect, and magnified

• Real, inverted, and magnified

• Virtual, erect, and diminished

• Virtual, inverted, and diminished

What type of image is formed by a concave lens when the object is at infinity?

• Virtual, erect, and highly diminished

• Real, inverted, and magnified

• Virtual, inverted, and magnified

• Real, erect, and diminished