Card 3

Question 1

Definition of lens.Types of lens

Answer 1

a transmissive optical device which focuses or disperses a light beam by means of refraction.

1) concave (diverging)
2)convex (converging)

Question 2

Definition and formula of Snell’s law

Answer 2

the relationship between the angles of incidence and refraction

n1sinθ1=n2sinθ2

n1/θ1-incident index and angle
n2/θ2-refracted index and angle

Question 3

Describe the phenomena of total internal reflection of light.When does it occur?

Answer 3

when the incident beam is generally inside some material such as glass or plastic and is reflected at the glass-air interface

Question 4

Definition of Kirchoff’s rule

Answer 4

1) each element produces a unique line spectrum which may be used to identify the element
2) the dark lines in the absorption spectrum occur at the same wavelengths as the bright lines in the emission spectrum

Question 5

Definition of polarized light

Answer 5

Polarized light is a light wave which vibration occurs in a single plane

Question 6

Which substance is called optically active?Write down the Bio’s law

Answer 6

is a material said to be optically active if it causes rotation of the direction of polarization of light that passes through it.

θ=θ0 CT

θ0 -specific rotation of solution
C -the concentration of solution
T -length of a tube.