It takes 4 minutes to boil a quantity of water electrically. How long will it take to boil same quantity of water using the same heating coil but with the current doubled? (neglecting any external heat loss).

Mimie123

3 years ago

The answer is D
Ivt=Ivt
4mins=240s
Iv×240=2I ×v×t
v cancel v
t=240I÷2I=120s

Note 120s=2minutes
so option D is the correct answer

Gabfans

3 years ago

Heat= Ir²t
I²r t = I² r t
First t is given .....4 minutes
I² r × 4 = [2I]² × t
4 = 4 t
T= 1Min

silascs17

2 years ago

I^2Rt=2I^2Rt
I^2*4=2I^2*t
Square root both sides to get
2I=2I*root t
thus, 1=root t
square both sides
t = 1 minute

tinizhawd

5 years ago

pls what is D in the answer

isahdandare

5 years ago

The answer is 2 minutes
Ivt = Ivt
1x4 = 2t
t = 4/2
t = 2 minutes