Physics question 28 plz help me

a. I = 30 A

b. E = 1080000 J = 1080 KJ

c. ΔT = 12.86°C

d. Cost = $ 4.32  

Explanation:

a.

The current in the coil is given by Ohm's Law:

where,

I = current = ?

V = Voltage = 120 V

R = Resistance = 4 Ω

Therefore,

I = 30 A

b.

The energy can be calculated as:

E = 1080000 J = 1080 KJ

c.

For the increase in the temperature of water:

where,

m = mass of water = 20 kg

C = specific heat of water = 4.2 KJ/kg.°C

Therefore,

ΔT = 12.86°C

d.

First, we will calculate the total energy consumed:

Now, for the cost:

Cost = $ 4.32

measure their densities same density, same sub

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27