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melamori03 [73]

3 years ago

14

Why is an iron core needed in an electromagnet?

1 answer:

ella [17]3 years ago

4 0

An iron core is needed in an electromagnet because it serves to increase the magnetic field created. It has a ferromagnetic properties. <span>An </span>electromagnet<span> is essentially just a battery attached to a coil of wire wrapped around a metal</span>core<span>. </span>

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Why are some atoms radioactive

Dmitry_Shevchenko [17]

Atoms<span> are made of three types of sub-atomic particle: neutrons and protons in the nucleus and electrons orbiting the nucleus. </span>Some<span> materials are </span>radioactive<span> because the nucleus of each </span>atom<span> is unstable and gives out nuclear radiation in the form of alpha particles, beta particles or gamma rays.</span>

8 0

3 years ago

Is there more forms of energy of there than :

bogdanovich [222]

Motion of things cause the energy such as the nuclear and the chemicals around temperature traveles

7 0

3 years ago

How will a current change if the resistance of a circuit remains constant while the voltage across the circuit decreases to half

beks73 [17]

Answer:

1. The current will drop to half of its original value.

Explanation:

The problem can be solved by using Ohm's law:

$V=RI$

where

V is the voltage across the circuit

R is the resistance of the circuit

I is the current

We can rewrite it as

$I=\frac{V}{R}$

In this problem, we have:

- the resistance of the circuit remains the same: R' = R

- the voltage is decreased to half of its original value: $V'=\frac{V}{2}$

So, the new current will be

$I'=\frac{V'}{R'}=\frac{V/2}{R}=\frac{1}{2}\frac{V}{R}=\frac{I}{2}$

so, the current will drop to half of its original value.

4 0

3 years ago

g An astronaut must journey to a distant planet, which is 189 light-years from Earth. What speed will be necessary if the astron

Butoxors [25]

Answer:

The value is $v = 2.999 *10^{8} \ m/s$

Explanation:

From the question we are told that

The time taken to travel to the planet from earth is $t = 189 \ light-years$

The time to be spent on the ship is $t_{s} = 12 \ years$

Generally speed can be obtained using the mathematical relation represented below

$t_s = 2 * t * \sqrt{1 - \frac{v^2}{c^2 } }$

The 2 in the equation show that the trip is a round trip i.e going and coming back

=> $12 = 2 * 189 * \sqrt{1 - \frac{v^2}{(3.0*10^{8})^2 } }$

=> $v = 2.999 *10^{8} \ m/s$

5 0

3 years ago

A 0.45-m metal rod moves 0.11 m in a direction that is perpendicular to a 0.80-T magnetic field in an elapsed time of 0.036 s. A

Gwar [14]

Answer:

1.1 V

Explanation:

L = 0.45 m

d = 0.11 m

B = 0.80 T

t = 0.036 s

Let e be the emf.

e = B v L

e = 0.80 x 0.11 x 0.45 / 0.036 = 1.1 V

3 0

4 years ago

Read 2 more answers