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3 years ago

13

Turning a magnet very quickly would be BEST used to create A) radiation. Reactivate B) light waves. Reactivate C) an electric cu

rrent. D) a convection current.

2 answers:

Andreyy893 years ago

4 0

Answer: C) an electric current

Explanation:

Changing magnetic field induces electromotive force which results in electric current to flow in conducting wire.

<u>From Faraday's Law:</u>

induced emf,

$e = -N \frac{\Delta B A}{\Delta A}$

Thus, when magnet is quickly turned, a change in magnetic field would produce an electric current.

Softa [21]3 years ago

3 0

<h2>Answer:</h2>

<u>Turning a magnet very quickly would be BEST used to create an electric current</u>

<h2>Explanation:</h2>

In Electromagnetic waves electric field produces magnetic field and vice versa. A moving magnet can produce electric current. Dynamo is the best example for it. In dynamo armature is rotated between the magnets which results in the development of electric field and hence an electric current is produced in it.

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Answer:

refraction

Explanation:

but this is easy so why

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3 years ago

A 5 kg box drops a distance of 10 m to the ground. If 70% of the initial potential energy goes into increasing the internal ener

Elina [12.6K]

Answer:

Explanation:

From the given information:

The initial PE $(PE)_i$ = m×g×h

= 5 kg × 9.81 m/s² × 10 m

= 490.5 J

The change in Potential energy P.E of the box is:

ΔP.E = $P.E_f -P.E_i$

ΔP.E = 0 - $(PE)_i$

ΔP.E = $-P.E_i$

If we take a look at conservation of total energy for determining the change in the internal energy of the box;

$\Delta P.E + \Delta K.E + \Delta U = 0$

$\Delta U = -\Delta P.E - \Delta K.E$

this can be re-written as:

$\Delta U =- (-\Delta P.E_i) - \Delta K.E$

Here, K.E = 0

Also, 70% goes into raising the internal energy for the box;

Thus,

$\Delta U =(70\%) \Delta P.E_i-0$

$\Delta U =(0.70) (490.5)$

ΔU = 343.35 J

Thus, the magnitude of the increase is = 343.35 J

7 0

3 years ago

Two long, straight wires both carry current to the right, are parallel, and are 25 cm apart. Wire one carries a current of 2.0 A

Artemon [7]

Answer:

x = 7.14 meters

Explanation:

It is given that,

Current in wire 1, $I_1=2\ A$

Current in wire 2, $I_2=5\ A$

Distance between parallel wires, r = 25 cm

Let at P point the net magnetic field equal to 0. The magnetic field at a point midway between the is given by :

$B=\dfrac{\mu_oI}{2\pi r}$

Let the distance is x from wire 1. So,

$\dfrac{I_1}{r}=\dfrac{I_2}{(0.25-r)}$

$\dfrac{2}{r}=\dfrac{5}{(25-r)}$

$x=\dfrac{50}{7}\ m$

x = 7.14 meters

So, the magnetic field will be 0 at a distance of 7.14 meters from wire 1. Hence, this is the required solution.

6 0

3 years ago

A virtual image is formed 17.0 cm from a concave mirror having a radius of curvature of 39.0 cm. (a) Find the position of the ob

Wittaler [7]

Explanation:

Image distance, v = -17 cm (-ve for virtual image)

Radius of curvature of concave mirror, R = 39 cm

Focal length, f = -19.5 cm (-ve for a concave mirror)

(a) Using mirror's formula as :

$\dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f}$

$\dfrac{1}{u}=\dfrac{1}{f}-\dfrac{1}{v}$

$\dfrac{1}{u}=\dfrac{1}{-19.5}-\dfrac{1}{(-17)}$

u = 132.6 cm

So, the object is placed 132.6 cm in front of the mirror.

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$m=\dfrac{-17}{132.6}$

m = -0.128

Hence, this is the required solution.

7 0

3 years ago

What is the derivative of x^2 - x + 3 at the point x = 5?

Hunter-Best [27]

Answer:

9

Explanation:

d/dx (x² - x + 3)

= 2x - 1

when x = 5,

2x-1

= 2(5) - 1

= 10 - 1

= 9

5 0

3 years ago