Обычная лампа накаливания мощностью 60 Вт создает световой поток 500 лм. Оцените световую эффективность лампы, т.е определите, какая доля мощности лампы приходится на излучение в видимой части спектра. Источник света в 1 кд в полосе частот видимого света создает поток излучения, равный 20,3 мВт.

1. Fill in the questing tag (Выберите правильную форму разделительного вопроса)

John didn’t collect the cans and newspapers, ….?

 a) didn’t he?      b)hasn’t he?       c)did he?

You like planting flowers, …..?

a) do you?          b)don’t you?       c)aren’t you?

Penguins are amazing animals, ….?

a) aren’t they?     b) don’t they?     c)are they?

She has made her one-off donation, ….?

a) hasn’t she?       b) has she?       c) is she?

He built a nesting box, …..?

a) did he?            b) didn’t he?     c)doesn’t he?

2. Choose the correct form of the verb (Выберите правильную форму глагола)

He _____ a lot of mistakes in last test.

a) have made      b) have been making     c) made

Pupils of our class _____ in five years.

a) meet               b)will meet           c) met

I _____ to tapes when they came.

 a) listened         b)was listening       c)were listening

Mark _____ to get a bigger vocabulary.

a) wants            b)have wanted         c) want

We _____ film in the original now.

a) watch        b)watched       c)are watching

I ……. the piano for 3 years.

a) have been playing        b) have played   c) play

3. Choose the right option. (Выберите верный вариант):

Brian is a very .................. boy and the best student in his class.

a. intelligent                   b. glance                            c.pipe

I like beautiful……………… in our village.

a. public                       b. dictionary                c. landscapes

John lives in the country because he likes the friendly and ………… people.

a. helpful                     b. heavy                               c. crowded

He can speak three ….: English, German and French.

a. languages         b. knowledge                 c. nationality

The athlete broke the world …….……. for the 100 m race.

a. idea                         b. record                             c. advice

There's аn ............... with Вrаd Pitt in today's newspaper.

a. interview                  b. message                         c. weather

Swimming is not ………. in this river.

a. allowed              b. polluted                               c. polite

Fаmоus people such as actors and sportsmen аrе …..…... fоr  tееnаgеrs.

a. role models                    b. school assignments              c. headphones

… they travel by bicycle every weekend.

a. To keep fit                  b. Figure skating            c. Hardly sleep

I find ………….. the most stressful.

a. taking care with your parents      b. getting enough sleep        c. arguing   with parents

The book is very …………

a. bored                           b. boring                        c. bore

2004 was the year ………… the Olympic Games were held in Athens.

a. when                          b. who                               c. which

I prefer classical music because it is ……………than rock music.

a. relax                       b. more relaxing                 c. most relaxing

If you have a headache, you ………… take a pain killer

a. should                     b. has                                  c. could

I did it ……….

a. myself                        b. herself                       c. itself

Have you ………… eaten candy floss?

a. ever                         b. always                            c. tomorrow

Is there …………. milk?

a. some                                b. many                             c. any

He is the ……….. boy in the class.

a. tallest                         b. tall                               c. taller

I bought a ………. blue dress.

a. Italian                   b. velvet                              c. nice

There is a ………….. of tea.

a. cup                        b. packet                            c. can