Question

Напруга на клемах реостата становить 5 В, а сила струму в його обмотці 0,8A. Визначте:а) опір обмотки реостата;б) споживану потужність;в) роботу, яку виконує електричний струм вобмотці реостата за 2 хв.​

Answer 1

Ответ:

а) R=U/I; R=5/0,8=6,25 Ом

б) P=UI; P=5*0,8=4 Вт

в) A=Pt; A= 4*120=480 Дж

Answer 2

Calculation of Resistance:

To determine the resistance of the coil of the rheostat, we can use Ohm's Law, which states that the resistance (R) is equal to the voltage (V) divided by the current (I). In this case, the voltage across the rheostat terminals is 5V, and the current flowing through its coil is 0.8A.

Using Ohm's Law, we can calculate the resistance as follows:

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

Substituting the given values:

R = 5V / 0.8A

Calculating the result:

R = 6.25 ohms

Therefore, the resistance of the coil of the rheostat is 6.25 ohms.

Calculation of Power Consumption:

To determine the power consumption, we can use the formula P = VI, where P is the power, V is the voltage, and I is the current. In this case, the voltage across the rheostat terminals is 5V, and the current flowing through its coil is 0.8A.

Using the formula, we can calculate the power consumption as follows:

Power (P) = Voltage (V) * Current (I)

Substituting the given values:

P = 5V * 0.8A

Calculating the result:

P = 4 watts

Therefore, the power consumption of the rheostat is 4 watts.

Calculation of Work Done:

To calculate the work done by the electric current in the coil of the rheostat over a period of 2 minutes, we need to know the power consumption and the time.

The formula for work (W) is given by W = Pt, where W is the work, P is the power, and t is the time.

Using the given power consumption of 4 watts and the time of 2 minutes (or 120 seconds), we can calculate the work done as follows:

Work (W) = Power (P) * Time (t)

Substituting the given values:

W = 4 watts * 120 seconds

Calculating the result:

W = 480 joules

Therefore, the work done by the electric current in the coil of the rheostat over a period of 2 minutes is 480 joules.