Transformers are an essential part of the National Grid. What are they used for?To convert electricity from from a.c. to d.c. and vice versaTo adjust the supply of electricity according to how much energy is needed at a given timeTo improve the efficiency with which electrical energy can be transmitted around the countryTo allow energy to be transferred from one energy store to another2What name is given to the type of transformer which allows for the potential difference (‘voltage’) at which electricity is delivered to be increased?A high voltage transformerA boost transformerA step-up transformerA jump-up transformer3A current of 0.5 kA is flowing through a cable of resistance 20 Ω. Calculate the power dissipated in the cable.5 × 106 W10 W10 kW5 W4There is a potential difference of 250 V across an electrical cable. Calculate the amount of energy dissipated in the cable when a current of 100 A flows through it for 10 seconds.25 J2.5 J25,000 J250,000 J5A high voltage power cable transmits electrical energy with an efficiency of 0.8. If 2 × 107 W of electrical power is supplied to one end of the cable, how much is transmitted to the opposite end?1.6 × 109 W4 × 106 W2.5 × 107 W1.6 × 107 W
Question
Transformers are an essential part of the National Grid. What are they used for?To convert electricity from from a.c. to d.c. and vice versaTo adjust the supply of electricity according to how much energy is needed at a given timeTo improve the efficiency with which electrical energy can be transmitted around the countryTo allow energy to be transferred from one energy store to another2What name is given to the type of transformer which allows for the potential difference (‘voltage’) at which electricity is delivered to be increased?A high voltage transformerA boost transformerA step-up transformerA jump-up transformer3A current of 0.5 kA is flowing through a cable of resistance 20 Ω. Calculate the power dissipated in the cable.5 × 106 W10 W10 kW5 W4There is a potential difference of 250 V across an electrical cable. Calculate the amount of energy dissipated in the cable when a current of 100 A flows through it for 10 seconds.25 J2.5 J25,000 J250,000 J5A high voltage power cable transmits electrical energy with an efficiency of 0.8. If 2 × 107 W of electrical power is supplied to one end of the cable, how much is transmitted to the opposite end?1.6 × 109 W4 × 106 W2.5 × 107 W1.6 × 107 W
Solution
-
Transformers are used to improve the efficiency with which electrical energy can be transmitted around the country. They allow energy to be transferred from one energy store to another.
-
The type of transformer which allows for the potential difference (‘voltage’) at which electricity is delivered to be increased is called a step-up transformer.
-
The power dissipated in a cable can be calculated using the formula P=I^2*R, where I is the current and R is the resistance. So, P = (0.5 kA)^2 * 20 Ω = 5 × 10^6 W.
-
The amount of energy dissipated in a cable can be calculated using the formula E=VIt, where V is the voltage, I is the current, and t is the time. So, E = 250 V * 100 A * 10 s = 250,000 J.
-
The amount of power transmitted to the opposite end of a high voltage power cable can be calculated by multiplying the power supplied by the efficiency. So, P = 2 × 10^7 W * 0.8 = 1.6 × 10^7 W.
Similar Questions
Which of the following types of transformers is used in distributing electricity to consumers?
What is the primary function of a transformer?a.To transfer electrical energy between circuitsb.To convert mechanical energy into electrical energyc.To amplify electrical signalsd.To convert electrical energy into mechanical energy
Why a transformer cannot be used to step up D.C. voltage?
Evaluate the effectiveness of using a transformer in electrical energy transmission over long distances.
All of the following statements about transformers are true, except:Group of answer choicesTransformers have two coil windings.Transformers can convert low voltage to high voltage.Transformers can convert high amperage to low amperage.Transformers only operate if the input current stays the same.
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.