The formula shown below is used to calculate the energy released when a specific quantity of fuel is burned. calculate the energy released by a burning sample of fuel if the temperature of 100g of water was raised by 20 °c. (specific heat capacity of water = 4200j/kg °c)

8400 J

Explanation:

The formula referenced in the question is:

Where:

 is the thermal energy

is the mass  of the water sample

 is the specific heat capacity of  water

 is the variation in temperature

Solving:

 This is the thermal energy released

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