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

the device is called “ rocket engine”