# Electric Energy Questions I

## Subject of electric circuits. Energy calculations in electric circuits. The relation between power and energy. Finding the amount of energy that any resistor consumed. Questions and its solutions.

Question – 1 In the circuit in the figure, R1 = 14 Ω, R2 = 10 Ω, R3= 9 Ω, R4 = 15 Ω, R5 = 6 Ω, R6 = 4 Ω

The supply voltage of the circuit is 110 V.

The energy that used in the resistor R1 in 1 second is W1 and the energy that used in the resistor R6 in 1 second is W6.

How many Joule is the sum of the W1 + W6

A) 348.5             B) 430.46               C) 468.35

D) 642                E) 765.52

Question - 2 In the circuit shown in the figure, R1 = 6 Ω, R2 = 4 Ω, R3 = 7 Ω, R4 = 12 Ω, R5 = 4 Ω, R6 =9 Ω

The energy consumed in 10 minutes in the resistor R2 is W2 .

Voltage of the supply source is 42 V.

How many Joule is the W2?

A) 5400                 B) 6200               C) 7100

D) 7800                 E) 8500

Question – 3

Power of an electric machine is 80 W.

How much energy consume does this machine in 1.5 hours?

A) 789               B) 654               C) 432

D) 365               E) 298

Question – 4

A bulb of 50 W operates with voltage of 110 V.

How many ohm is the resistance of this bulb?

A) 675               B) 550                C) 450

D) 375               E) 250

Question – 5

An electric appliance consumes energy of 270 kJ in 3 hours.

The resistance of this appliance is 100 Ohm.

How many amperes is the current flowing through this appliance.

A) 0.2             B) 0.5                   C) 1

D) 1.5             E) 2

Question – 6 In the circuit shown in the figure, R1 = 5 Ω, R2 = 7 Ω, R3 = 3 Ω, R4 = 2 Ω, R5 = 1 Ω, R6 = 3 Ω, R7 = 5 Ω, R8 = 8 Ω

The consumed energy in the resistor R1 in 30 minutes is 9 kJ.

Voltage of the supply source is

A) 120               B) 100                C) 80

D) 60                 E) 50

Question – 7 in the figure is seen a water heater. Mass of the water is 250 g, its temperature is 10 °C. The switch is turned off along 3 minutes.

In last case, temperature of the water is being 90 °C.

Resistance of the heater is

(csu = 1 kal/g °C, 1 kalori=4 Joule)

A) 6.2 Ω                    B) 8.1 Ω                   C) 10 Ω

D) 12.5 Ω                  E) 18 Ω

Question – 8

178 kWh is

A) 298750 kJ

B) 320000 kJ

C) 465800 kJ

D) 554000 kJ

E) 640800 kJ

Question – 9

200 J energy is required to increase the temperature of a room by 1 ° C.

A heater of 1500 Watts is operated for 3 hours per day.

1 kWh electric energy consumption price is 0.2 USD.

How much USD is the 1 month (30 days) electricity consumption cost of this device?

A) 270                 B) 300             C) 330

D) 410                 E) 450

Question – 10

240 J energy is needed to increase the temperature of a room by 1 ° C.

The temperature of the room is 5 ° C.

This room is heated with a heater of 1000 Watts.

1 kWh electric energy consumption price is 0.2 USD.

If the room temperature is increased from 5 ° C to 20 ° C, how many USD energy is spent?

A)3               B) 1,5            C) 0,8

D) 0,2           E) 0,1

Solutions Of These Questions

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December 4 2018

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