Answer:
To unlock a door and indicate to the person that the door is now unlocked
Explanation:
Schools all have doors locked. Visitors/parents need to press a button. That creates a buzz sound in the office, secretary presses a button to unlock the door. The person trying to enter the school hears a buzz and the secretary telling them to enter the building.
Answer:

Explanation:
The magnetic field B inside long solenoid with current I is given as

where
N is number of turn of solenoids = 1140 turns

I is current that passes through solenoid
L is length along which current pass = 0.350 m
plugging value to get required value of current


Answer:
The planet will move from east to west for a couple of months in the night sky.
Explanation:
Retrograde motion is an optical effect due to the fact that Earth rotates more quickly than the planet that apparently has a retrograde motion in the sky.
For example, Saturn has a slower speed in its orbit around the Sun. That means that the Earth will pass it, and that will give the effect that the planet is moving backward. That same scenario can be seen between two cars on a highway, the faster car will see the slower car when it passes as it is moving for a short fragment of time in backward.
Remember that the planets in the night sky move from west to east, in the case of a planet with retrograde motion, it will move from east to west for a couple of months.
Answer:
The answer is A.
Explanation:
To measure a temperature, you have degrees with Farenheight or Celsius. Meters are measured with a meter stick while grams and kilograms are measurments for weight.
Therefore, degrees Celsius is your answer.
Best of Luck to you!