Question

Calculate the heat generated when a current of 7 ampere passes through the resistance of 420Ω for 6

minutes. (Take J = 4.2 Joule/cal.)​

Answer 1

Required Answer :

The heat generated = 17,640,000 calorie

Given :

• Current = 7 ampere
• Resistance = 420 Ω
• Time = 6 minutes

To find :

• Heat generated

Concept :

Here, we are given the current, resistance and the time and we need to calculate the heat generated by the conductor. For that firstly we will convert the time from minutes into seconds. And then by using the following formula we will calculate the heat generated.

Formula to calculate the heat generated :-

• Q = I²RT

where,

• Q = Heat generated
• I = Current
• R = Resistance
• T = Time

Solution :

As we know,

• 1 minute = 60 seconds

In order to convert the time from minutes into seconds, multiply it by 60.

⇒ Time = 6 minutes

⇒ Time = 6 × 60

⇒ Time = 3600 seconds

Calculating the heat generated :-

• Heat generated = I²RT

we have,

• I = 7 ampere
• R = 420 Ω
• T = 3600 s

Substituting the given values :-

⇒ Heat generated = (7)²(420)(3600)

⇒ Heat generated = 49 × 420 × 3600

⇒ Heat generated = 74,088,000

Heat generated = 74,088,000 J

As we know,

• 1 calorie = 4.2 J

⇒ Heat generated = 74,088,000 ÷ 4.2

⇒ Heat generated = 17,640,000

Therefore, the heat generated = 17,640,000 calorie