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3 years ago

The electric current in a wire is 1.5A. How many electrons flow past a given point in a time of 2s?

Physics

1 answer:

kipiarov [429]3 years ago

5 0

Answer:

The amount of electrons that flow in the given time is 3.0 C.

Explanation:

An electric current is defined as the ratio of the quantity of charge flowing through a conductor to the time taken.

i.e I = $\frac{Q}{t}$ ...................(1)

It is measure in Amperes and can be measured in the laboratory by the use of an ammeter.

In the given question, I = 1.5A, t = 2s, find Q.

From equation 1,

Q = I × t

= 1.5 × 2

= 3.0 Coulombs

The amount of electrons that flow in the given time is 3.0 C.

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A train is moving in a straight railway where it covered one third of the distance with

Alexxandr [17]

Answer:

The average speed of the train is 45 km/h

Explanation:

Speed

It's defined as the distance (d) per unit of time (t) traveled by an object. The formula is:

$\displaystyle v=\frac{d}{t}$

Let's call x the total distance covered by the train. It covered d1=1/3x with a speed of v1=25 km/h. The time taken is calculated solving for t:

$\displaystyle t_1=\frac{d_1}{v_1}$

$\displaystyle t_1=\frac{1/3x}{25}$

$\displaystyle t_1=\frac{x}{75}$

Now the rest of the distance:

d2 = x - 1/3x = 2/3x

Was covered at v2=75 km/h. Thus the time taken is:

$\displaystyle t_2=\frac{d_2}{v_2}$

$\displaystyle t_2=\frac{2/3x}{75}$

$\displaystyle t_2=\frac{2x}{225}$

The total time is:

$\displaystyle t_t=\frac{x}{75}+\frac{2x}{225}$

$\displaystyle t_t=\frac{3x}{225}+\frac{2x}{225}$

$\displaystyle t_t=\frac{5x}{225}$

Simplifying:

$\displaystyle t_t=\frac{x}{45}$

The average speed is the total distance divided by the total time:

$\displaystyle \bar v=\frac{x}{\frac{x}{45}}$

Simplifying:

$\boxed{\displaystyle \bar v=45\ km/h}$

The average speed of the train is 45 km/h

5 0

3 years ago

Which device uses a rotating magnetic field to produce an electric current?

Kay [80]

The correct answer is C) a motor.
In particular, we are talking about an AC motor, which produces an alternating current. In an AC motor, a coil is immersed in a rotating magnetic field. Due to the motion of the magnetic field,the angle between the direction of the field and the surface enclosed by the coil changes. As a result, the magnetic flux through the coil changes over time (the magnetic flux is given by:
 $\phi=BAcos\theta$ 
where B is the intensity of the magnetic field, A is the area enclosed by the coil and $\theta$ is the angle between the direction of B and the perpendicular to the plane of the coil). For Faraday-Newmann-Lenz law, this change in flux induces an electromotive force (emf) into the coil, according to:
 $emf=- \frac{d \Phi}{dt}$ 
where the numerator is the variation of magnetic flux and dt is the time interval. This emf in the coil produced an electrical current in the circuit.

7 0

3 years ago

Read 2 more answers

Saatlemati

vodomira [7]

Answer:

what are u asking there isnt a question

3 0

3 years ago

Can you guys help me

andreev551 [17]

B will be the answer