Science help please! Urgent!

Physics

2 answers:

iren2701 [21]3 years ago

3 0

In direct current (DC), the electric charge (current) only flows in one direction. Electric charge in alternating current (AC), on the other hand, changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.

Karo-lina-s [1.5K]3 years ago

3 0

26) The force felt py a charged particle in a magnetic field is given by Lorentz force:
F=q(vxB) where q is charge, v is velocity, and B is the field vector.
Positive particles have positive charge +q
Negative particles have negative charge -q
So the forces are in opposite directions (they spiral in opposite directions).

27) The coil of a galvanometer is put in a constant magnetic field. When a current, I, is passed through the coil it creates a magnetic moment M=NIA where N is the turns of wire, A is the area of the loop, and I is current. This moment feels a torque in the field is MxB where "x" is the cross product. So the coil is rotated in the field by an amount proportional to its current.

28) DC travels in one direction only. AC changes directions twice per period. This makes it possible to transform the voltage later on, since Faraday's law requires the magnetic field created by a current to be changing in time. This is the main reason we use AC

You might be interested in

A force (5ỉ - ;)N moves an object from the point P (1,3) m to the point Q (3, 8) m.

natita [175]

Answer:

b) 5 J

Explanation:

Work is the energy transferred by an object when acted by a force along a displacement. Work is the product of force and displacement. The SI unit of work is the joules (J)

To calculate the work done by the force, we have to first get the displacement (D) of the object. Hence:

Displacement (D) = Q(3, 8) - P(1, 3) = (3 - 1, 8 - 3) = (2, 5) = 2i + 5j

The work done is the dot product of the force and the displacement. Force = 5i - j. Hence:

Work done = (5i - j)(2i + 5j) = 10 - 5 = 5 J

3 0

3 years ago

What single property was the most important in jesseca's material

jek_recluse [69]

Answer:

Jesseca wanted to create a material that reflected most of the light that fell on it.

Explanation: The Graphite was the material in the passage that had reflected most of the light.

6 0

3 years ago

our iclicker operates at a frequency of approximately 900 mhz (900x106 hz). what is the approximate wavelength of the em wave pr

Elena-2011 [213]

wavelength of the EM wave produced by your iclicker is 0.33 m.

<h3>What makes an EM wave?</h3>

When an electric field (illustrated in red arrows) combines with a magnetic field, electromagnetic waves are generated (which is shown in blue arrows). An electromagnetic wave's magnetic and electric fields are perpendicular to each other and to the wave's direction.
A changing magnetic field causes a changing electric field, and vice versa—the two are inextricably related. Electromagnetic waves are created by changing fields. Electromagnetic waves, unlike mechanical waves, do not require a medium to propagate.

The clicker emits EM (electromagnetic) wave which travels at the speed of light, that is

v = 3 x 10⁸ m/s

The frequency is

f = 900mHz = 9 x 10⁸ Hz

velocity = frequency * wavelength, the wavelength, λ, is given by

fλ = v

λ = v/f

= (3 x 10⁸ m/s) / (9 x 10⁸ 1/s)

= 1/3 m = 0.333 m

To learn more about electromagnetic waves refer,

brainly.com/question/25847009

#SPJ1