Answer: The correct statements are ; A and B.
Explanation:
The strength of the magnetic field(B) in an electromagnet can be calculated using formula:

= Relative permeability
N = number of turns
I = Current in the wire of the solenoid
L = length of the solenoid or electromagnetic
As we can see from the formula:


So, by increasing the turns and increasing current flowing through wire one can increase the strength of an electromagnet.
Hence, the correct statements are ; A and B.
Answer: 150 kPa
Explanation:
Given that,
Original volume of gas V1 = 30L
Original pressure of gas P1 = 105 kPa
New pressure of gas P2 = ?
New volume of gas V2 = 21L
Since pressure and volume are given while temperature is constant, apply the formula for Boyle's law
P1V1 = P2V2
105 kPa x 30L = P2 x 21L
3150 kPa L = P2 x 21L
P2 = 3150 kPa L / 21 L
P2 = 150 kPa
Thus, 150 kPa of pressure is required to compress the gas
Answer:
.....false
Explanation:
the particles in the air are packed apart whereas the particles in steel are closely packed and sound travel faster in solids than in gasses..