Physics 2008 JAMB Past Questions - Question 22: A block of aluminium is heated electrically by a 25 W heater .If the temperture rises by 100C in 5 minutes ,the heat capacity of the aluminium is

Correct Answer

B

Explanation

Heat supplies = Heat gainedP x t = c25 x 5 x 60 = x 10C = 25 x 5 x 60 = 750jk-1 10
To find the heat capacity (C) of the aluminum block, you can use the formula:

Q = C * ΔT

Where:
Q is the heat energy transferred (in joules),
C is the heat capacity (in joules per degree Celsius, J/°C), and
ΔT is the change in temperature (in degrees Celsius, °C).

In this case, you have the following information:

1. Power of the heater (P) = 25 W (watts)
2. Time (t) = 5 minutes = 300 seconds
3. Change in temperature (ΔT) = 100°C

First, calculate the heat energy (Q) using the power formula:

Q = P * t
Q = 25 W * 300 s
Q = 7500 J (joules)

Now that you have the heat energy (Q), you can use it to find the heat capacity (C):

Q = C * ΔT

7500 J = C * 100°C

Now, solve for C:

C = 7500 J / 100°C
C = 75 J/°C

So, the heat capacity of the aluminum block is 75 joules per degree Celsius (J/°C).