(c)
A television is switch
television, but only
his switched on inside a room. A person outside the room can hear the
on, but only when the door is open
Person
Wall
Television
Door
Wall
When the door is open the person can hear the sound but cannot see the television,
Explain why

The sound waves pass through the door and will then go further from the space near the door making the sound hear outside the door also.

Explanation:

Waves can twist around corners in view of an impact called diffraction. The sum that a wave will twist around a corner as a result of diffraction is about equivalent to its frequency. So it is a lot simpler to see the bowing of the sound waves, since it is around a million times greater than the bowing of the light waves.

As the waves pass through the door, they bend and travel into the space near the door. Because they spread out into the space beyond the door, a person near the doorway can hear sounds from inside the room.

he made 11 calls in one day

answer: 31, 5556. 952 seconds