Question

В Электроплитке при силе тока 5 А за 3 мин выделилось 1080 кДж тепла. Рассчитайте сопротивление плитки.

Answer 1

По закону Джоуля - Ленца:

Q = I²·R·t

Сопротивление электроплитки:

R = Q / (I²·t)

R = 1 080 000 / (5²·3·60) = 240 Ом

Answer 2

Calculation of Resistance in an Electric Stove

To calculate the resistance of the electric stove, we can use the formula:

Resistance (R) = Voltage (V) / Current (I)

In this case, we are given the current (I) as 5 A and the time (t) as 3 minutes. However, we need to convert the time to seconds before proceeding with the calculation.

1 minute = 60 seconds

Therefore, 3 minutes is equal to 3 * 60 = 180 seconds.

Now, let's proceed with the calculation:

Resistance (R) = Voltage (V) / Current (I)

We are not given the voltage (V) directly, but we are given the amount of heat (Q) produced by the stove, which is 1080 kJ (kilojoules). We can use the formula:

Heat (Q) = Voltage (V) * Current (I) * Time (t)

Substituting the given values:

1080 kJ = V * 5 A * 180 s

To convert kilojoules to joules, we multiply by 1000:

1080 kJ = V * 5 A * 180 s * 1000

Simplifying:

1080 kJ = V * 900000 A * s

Now, we can solve for voltage (V):

V = (1080 kJ) / (900000 A * s)

Converting kilojoules to joules:

V = (1080 * 1000 J) / (900000 A * s)

Simplifying:

V = 1.2 V

Now that we have the voltage (V) and current (I), we can calculate the resistance (R):

Resistance (R) = Voltage (V) / Current (I)

R = 1.2 V / 5 A

R = 0.24 Ω

Therefore, the resistance of the electric stove is 0.24 Ω.