Answer:
u need to put ur statements up for an answer
Answer:
1) The strength of the electromagnet increases → Place a magnetic core inside the coil of wire
2) The electromagnet turns off → Turn off the battery supply
3) The poles of the electromagnet reverse → Change the direction in which the current flows
Explanation:
when current passes through a coil it behaves a an electromagnet.
Magnetic field strength is given by
B = μ N I
N is no of turns and
I is the current through coil
μ is permeability of the medium or core in the coil.
1). Magnetic core increase permeability μ so it will strengthen magnetic field:
B = <u>μ</u> N I
2). When the battery turns off current becomes zeroi.e I=0
So B = μ N * 0
⇒ B = 0
so electromagnet turns off
3). Direction of magnetic field can be determine by right hand rule, i.e curl the fingers in the direction of current, thumb will point in the direction of north pole.
so changing current direction will change direction of magnetic field.
Answer:
-D) Identify a question, make observations, create a hypothesis, and then set up an experiment to test the hypothesis because need to follow the steps to do the experiment properly.
Answer:
1.48 kg
Explanation:
mass of copper = 4 kg
Decrease in temperature of copper = 36.9°C
increase in temperature of water = 9.20°C
Let the mass of water is m.
Specific heat of water = 4181 J/Kg°C
Specific heat of copper = 385 J/kg°C
According to the principle of caloriemetery
Heat lost by copper = heat gained by water
mass of copper x specific heat of copper x decrease in temperature = mass of water x specific heat of water x increase in temperature
4 x 385 x 36.9 = m x 4181 x 9.20
56826 = 38465.2 m
m = 1.48 kg
Thus, the mas of water is 1.48 kg.
mas of water
Resistor 1 and three are in series so the total resistance is 1.