Прочитайте текст и выберите утверждение, соответствующее содержанию текста
A student is experimenting with the remote control at the moment. He is putting a piece of white card about 2 cm in front of the control. The control is still operating because the beam is reflecting off the card and then the wall behind.
Now the student is using a piece of black card instead of the white card. This time the signal is not reaching the receiver. Why?
Answer: the black surface absorbs the infrared rays and does not reflect it back into the room.
Now the student is not using a piece of black card instead of the white card.
Now the teacher is using a piece of black card instead of the white card.
Now the student is using a piece of white card instead of the black card.
Now the student is using a piece of black card instead of the white card.