All categories

3 years ago

How are step up transformers used in the transmission of electrical energy

Physics

1 answer:

tensa zangetsu [6.8K]3 years ago

8 0

Answer:

Transformers are used to increase or decrease the voltage of AC currents

Explanation:

A transformer is a device consisting of two coils (called primary and secondary coil) wrapped at the two sides of a soft iron core. When an AC current is present in the primary coil, it induces a magnetic field inside the core, and the presence of this changing magnetic field induces a voltage (and a current) into the secondary coil.

The voltages in the primary and the secondary coil are related by the transformer equation:

$\frac{V_p}{V_s}=\frac{N_p}{N_s}$

where

Vp, Vs are the voltages in the primary and secondary coil

Np, Ns are the number of turns in the primary and secondary coil

There are two types of transformers:

- Step-up transformers: these have $N_s > N_p$ , so that $V_s > V_p$ , which means that they increase the voltage. They are used to increase the voltage of the AC current produced by the power plants, before being sent into the transmission lines.

- Step-down transformers: these have $N_s < N_p$ , so that $V_s < V_p$ , which means that they decrease the voltage. They are used at the end of the transmission lines, before the houses, in order to decrease the voltage and allow the household appliances to work properly (in fact, household appliances need lower voltages to work)

You might be interested in

Tourists covered 255 km for a 4-hour ride by car and a 7-hour ride by train. what is the speed of the train, if it is 5 km/h gre

LekaFEV [45]

The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:
$S_c = v_c t_c$
where
$v_c$ is the car's speed
$t_c = 4 h$ is the duration of the car ride

Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:
$S_t = v_t t_t$

The total distance covered is S=255 km, which is the sum of the distances covered by car and train:
$S=255 km = S_c + S_t$
which becomes
$255 = 4 v_c + 7 v_t$ (1)
we also know that the train speed is 5 km/h greater than the car's speed:
$v_t = 5 + v_c$ (2)

If we put (2) into (1), we find
$255 = 4v_c + 7(5+v_c)$
and if we solve it, we find
$v_c = 20 km/h$
$v_t = 25 km/h$

So, the car speed is 20 km/h and the train speed is 25 km/h.

4 0

4 years ago

A Capacitor is a circuit component that stores energy and can be charged when current flows through it. A current of 3A flows th

ddd [48]

Answer:

$8\mu C$

Explanation:

t = Time taken = $2\mu s$

i = Current = 3 A

q(0) = Initial charge = $2\mu C$

Charge is given by

$q=\int_0^t idt+q(0)\\\Rightarrow q=\int_0^{2\mu s} 3dt+2\mu C\\\Rightarrow q=3(2\mu s-0)+2\mu C\\\Rightarrow q=6\mu C+2\mu C\\\Rightarrow q=8\mu C$

The magnitude of the net electric charge of the capacitor is $8\mu C$

4 0

3 years ago

This nutrient can be hidden in food and has twice as many calories as other nutrients

vfiekz [6]

Protein has 4 cals carbs have 4 too. Fat however has 9.

6 0

3 years ago

Wavelength of blue photons 495 nm, what is the frequency? and what is the energy?

inessss [21]

Answer:

1.F: About 6*10^14 Hz

2.E: About 4*10^ -19 J

Explanation:

Frequency: We knew that the speed of a wave is its wavelength(λ)* frequency(f, in Hz). By the wave-particle duality we know we can calculate the frequency of light in the same way. So, c=495nm *f, f=c/495nm=> (299,792,458 m/s) / (4.95*10^-7 m)

=6.05*10^14 /s

Energy: The energy photon contains can be calculate by this formula-- E=hf

f is the frequency and h is Planck's constant which is about 6.62 ×10^-34 *m^2*kg/s (after dimensional analysis ) =6.62*10^ -34 J*s.

So, the energy of a blue photon is (6.05*10^14)*(6.62*10^-34)=40.051*10^-20= 4.051*10^-19 J

3 0

3 years ago

A sound wave has a speed of 345 m/s and a wavelength of 4.15 meters. What is the frequency of this wave?

Debora [2.8K]

Answer:

83 hertz

OPTION A

Explanation:

$wavelength = \frac{speed}{frequency}$

Given

wavelength=4.15m

speed=345 m/s

$frequency = \frac{speed}{wavelength} = \frac{345}{4.15}$

$frequency = 83 \: hertz$

I hope it helped you

5 0

3 years ago