Check your understanding

Exercise 1. Answer the following questions.

1. What is the most widely used optical device?

   1. The most widely used optical device is a telescope.

   2. The most widely used optical device is a prism.

   3. The most widely used optical devise is a microscope.

   4. The most widely used optical devise is a lens.

2. Which definition of the lens is correct?

   1. An optical system consisting of two or more refracting interfaces, at least one of which is curved.

   2. Nonplanar surface centered on a common axis.

   3. Two spherical segments coated with thin dielectric films.

   4. Optical system used for converging or diverging of light waves.

3. Which of these natural objects can we use as a lens?

   1. Our eyes

   2. A droplet of water

   3. Lake surface

   4. A pearl

Increase your vocabulary

Exercise 1. Find the Russian equivalents of the words listed below.

1	2
1) compound lens	сложная линза (объектив)
2) burning glasses	поверхность
3) concave lens	ничтожный
4) diverging	кривизна
5) curvature	вогнутая линза
6) negligible	форма
7) interface	рассеивающая
8) nonplanar	экран
9) surface	неплоский
10) wavelength	волновой фронт
11) shape	поверхность раздела
	зажигательные стёкла
	длина волны
	выпуклая линза

Exercise 2. Read and translate the collocations below.

That notwithstanding the fact, lenses date back, for the most part, tend to decrease, in other words, on the other hand, a millionth of a second.

Exercise 3. Match the synonyms.

Verbs

1	2
achieve	make
allow	wish
produce	consist
desire	let
coat	get
	require
	cover

Nouns

1	2
interface	photo
adjustment	pinhole
picture	surface
aperture	change
speed	device
	velocity
	image