A transformer is used to light a lamp rated 40w, 240v from a 400v A.C supply. Calculate:
A. The ratio of the number of turns of the primary to the secondary coil.
B. Current drawn from the main circuit if the efficiency of the transformer is 90%.​

Answers

Answer 1

Answer:1.81

(a) Explanation:the turn ratio= input voltage÷output voltage.

400÷220=1.81.

Don't know how to solve b part...


Related Questions

Two teams are playing tug-of-war. Team A, on the left, is pulling on the rope with an effort of 5000 N. If the rope is moving at a constant velocity, how hard and in which direction is team B pulling?
A. 2500 N to the left
B. 5000 N to the right
C. 2500 N to the right
D. 5000 N to the left

Answers

Explanation:

If Team A is on the left, B is on the right

if the force is constant, it means that the effort applied is equal.

So Team B is pulling 5000N to the right.

how does enormous energy get released from the sun​

Answers

Answer:

By nuclear fission

Explanation:

The sun generates enormous energy through the process of nuclear fusion.

The core or the innermost part of the sun is characterized by high temperature and pressure. These two factors cause the separation of nuclei from electrons and the fusion of hydrogen nuclei to form a  helium atom.

During the fusion process, energy is released.

Consider a satellite in a circular orbit around the earth. Why is it important to give a satellite a horizontal speed when placing it in orbit? What will happen if the horizontal speed is too small? What will happen if the speed is too large?

Answers

Answer:

In this case, the horizontal velocity of the rocket starts from the acceleration, so if its velocity drops to zero,

Explanation:

When a satellite is in orbit the most important force is the docking of gravity with the Earth

             F = m a

where the acceleration is centripetal and F is the force of universal attraction

centripetal acceleration is

             a = v² / r

             

             F = m v² / r

In this case, the horizontal velocity of the rocket starts from the acceleration, so if its velocity drops to zero, the force also drops to serious and the satellite steels to Earth.

The speed of the satellite is provides the speed, by local for smaller speeds in satellite, it descends in its orbits and when the speed is amate you have the energy to stop an orb to go to a higher orbit.

What kind of substance can you pour from one container into another without a change in volume

Answers

Liquid is the answer
Please mark brainliest please

Answer:

Liquids

Explanation:

Liquids take up the shape of the container it is poured into but will never change its volume.

1. Find the energy required to melt 255g of ice at 0°C into water at 0°C

Answers

Answer:

E = 85170 J (/ 85.2 kJ)

Explanation:

Take the latent heat of fusion of water be 334J / g.

From the equation E = ml,

E = energy required (unknown),

mass m = 255g,

latent heat of fusion l = 334J / g,

E = 255 x 334

E = 85170 J (/ 85.2 kJ)

Answer the following questions regarding the equation:

N₂ + 3H₂ → 2NH₃

1) indicates what type of reaction is
2) what represents the coefficients 3 and 2 in the previous reaction is done for
3) What would be missing in the previous equation to make it more accurate is

Answers

Explanation:

1) This is a synthesis reaction (two or more reactants combine to form a single product).

2) The coefficients are added to balance the reaction.

3) Adding the states of matter (solid, liquid, gas) will make the reaction more precise.

coma Narrows Bridge across the Puget Sound collapsed. The bridge was a suspension bridge. The wind blowing through the narrows matched the natural frequency of the bridge. This resulted in a large movement of roadway, which eventually caused the bridge to fail. What characteristic of waves caused the bridge to collapse

Answers

Answer:

amplitude

Explanation:

Amplitude is the characteristic of waves which caused the bridge to collapse.   Amplitude of a wave is the maximum amount of displacement of a particle occurs in the medium from its rest position. When the frequency of a wave reaches the natural frequency of the bridge, the oscillation of the bridge produce an amplitude where it causing the destruction of the bridge which is called Resonance. So we can say that amplitude is the characteristic of waves which is responsible for the collapse of the bridge.

Answer: C.interference, because constructive interference occurred when the wind frequency matched the natural frequency of the bridge

Explanation:

A pendulum at position A is released and swings through position B to position Con the other side.
B
1. Describe the total mechanical energy at each of the following positions. (3)
A.
B.
C

Answers

Explanation:

Given the conditions A,B and C when the pendulum is released, at point A the initial velocity of the pendulum is zero(0), the potential energy stored is maximum(P.E= max),

the conditions can be summarized bellow

point A

initial velocity= 0

final velocity=0

P.E= Max

K.E= 0

point B

initial velocity= maximum

final velocity=maximum

P.E=K.E

point C

initial velocity= min

final velocity=min

P.E= 0

K.E= max

when a 0.622kg basketbll hits the floor its velocit changes from 4.23m/s down to 3.85m/s up. if the averge force was 72.9N how much time was it in contact with the floor?

Answers

Answer:

Time, t = 3.2 ms

Explanation:

It is given that,

Mass of basketball, m = 0.622 kg

Initial velocity, u = 4.23 m/s

Final velocity, v = 3.85 m/s

Average force acting on the ball, F = 72.9 N

We need to find the time of contact of the ball with the floor. Let t is the time of contact. So,

[tex]F=ma\\\\F=\dfrac{m(v-u)}{t}\\\\t=\dfrac{m(v-u)}{F}\\\\t=\dfrac{0.622\times (3.85-4.23)}{72.9}\\\\t=0.0032\ s\\\\\text{or}\\\\t=3.2\ ms[/tex]

So, the ball is in contact with the floor for 3.2 ms.

A student throws a 120 g snowball at 7.5 m/s at the side of the schoolhouse, where it hits and sticks. What is the magnitude of the average force on the wall if the duration of the collision is 0.15 s

Answers

Answer:

The magnitude of the average force on the wall during the collision is 6 N.

Explanation:

Given;

mass of snowball, m = 120 g = 0.12 kg

velocity of the snowball, v = 7.5 m/s

duration of the collision between the snowball and the wall, t = 0.15 s

Magnitude of the average force can be calculated by applying Newton's second law of motion;

F = ma

where;

a is acceleration = v / t

a = 7.5 / 0.15

a = 50 m/s²

F = ma

F = 0.12 x 50

F = 6 N

Therefore, the magnitude of the average force on the wall during the collision is 6 N.

Oil at 150 C flows slowly through a long, thin-walled pipe of 30-mm inner diameter. The pipe is suspended in a room for which the air temperature is 20 C and the convection coefficient at the outer tube surface is 11 W/m2 K. Estimate the heat loss per unit length of tube.

Answers

Answer:

1.01 W/m

Explanation:

diameter of the pipe d = 30 mm = 0.03 m

radius of the pipe r = d/2 = 0.015 m

external air temperature Ta = 20 °C

temperature of pipe wall Tw = 150 °C

convection coefficient at outer tube surface h = 11 W/m^2-K

From the above, we assumed that the pipe wall and the oil are in thermal equilibrium.

area of the pipe per unit length A = [tex]\pi r ^{2}[/tex] = [tex]7.069*10^{-4}[/tex] m^2/m

convectional heat loss Q = Ah(Tw - Ta)

Q = 7.069 x 10^-4 x 11 x (150 - 20)

Q = 7.069 x 10^-4 x 11 x 130 = 1.01 W/m

The heat loss per unit length of tube should be considered as the 1.01 W/m.

Calculation of the heat loss:

Since

diameter of the pipe d = 30 mm = 0.03 m

radius of the pipe r = d/2 = 0.015 m

external air temperature Ta = 20 °C

temperature of pipe wall Tw = 150 °C

convection coefficient at outer tube surface h = 11 W/m^2-K

Now

area of the pipe per unit length A should be

= πr^2

 = 7.069*10^-4 m^2/m

Now

convectional heat loss Q = Ah(Tw - Ta)

Q = 7.069 x 10^-4 x 11 x (150 - 20)

Q = 7.069 x 10^-4 x 11 x 130

= 1.01 W/m

hence, The heat loss per unit length of tube should be considered as the 1.01 W/m.

Learn more about heat here: https://brainly.com/question/15170783

What can happen if a body moves through speed of light

Answers

As waves travel into the denser medium, they slow down and wavelength decreases.

Explanation:

The denser the medium the slower the waves (speed of light) travels.

◦•●◉✿When the body approaches the speed of light, the body's length appears to contract in the direction of travel, and its mass appears to increase from the point of view of a stationary observer. Only photons move to light velocity. They don´t have length.✿◉●•◦

Choose the friction which opposes the relative motion between surfaces in motion a.Static friction b.Kinetic friction c.Sliding friction d.Both kinetic and sliding friction

Answers

Answer:

d. Both kinetic and sliding friction

Explanation:

Kinetic friction, commonly known as sliding friction, happens when a body with its surfaces in contact is in relative motion with another. It's the frictional force slowing it down, and finally stopping a moving body. One can describe sliding friction as the resistance any two objects create while sliding against each other. It is often documented as the force required to hold a surface moving along another surface. It is determined by two variables- one is material of the object and another is its weight.

A ball has a mass of 0.25 kg and is moving to the right at 1.0 m/s. It hits a ball of mass 0.15 kg that is initially at rest. After the collision, the 0.15 kg ball moves off to the right with a velocity of 0.75 m/s. What is the final velocity of the 0.25 kg ball? 0.42 m/s to the right 0.42 m/s to the left 0.55 m/s to the right 0.55 m/s to the left

Answers

Answer:

C-0.55 m/s to the right

Explanation:

edg

Answer:

0.55 to the right

Explanation:

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