Question

Реостат сопротивлением 40 Ом рассчитан на максимальную силу тока 2 А. Можно ли включать этот реостат в цепь с напряжением 70 В? 100 В?

Answer 1

С напряжением 70-можно, с напряжением 100-нельзя.

Answer 2

Can a rheostat with a resistance of 40 Ohms and a maximum current of 2 Amps be connected to a circuit with voltages of 70V and 100V?

A rheostat is a variable resistor that can be used to control the flow of electric current in a circuit. It is designed to have a specific resistance value and a maximum current rating. In this case, the rheostat has a resistance of 40 Ohms and a maximum current rating of 2 Amps.

To determine if the rheostat can be connected to a circuit with voltages of 70V and 100V, we need to consider the power dissipation and the current flowing through the rheostat.

The power dissipation in a resistor can be calculated using the formula P = I^2 * R, where P is the power, I is the current, and R is the resistance.

For the rheostat with a resistance of 40 Ohms and a maximum current of 2 Amps, the maximum power dissipation can be calculated as follows:

P = (2 Amps)^2 * 40 Ohms = 160 Watts

Now let's consider the two voltage scenarios:

1. Voltage of 70V: - To calculate the current flowing through the rheostat, we can use Ohm's Law: I = V / R, where I is the current, V is the voltage, and R is the resistance. - I = 70V / 40 Ohms = 1.75 Amps - The current flowing through the rheostat is 1.75 Amps, which is within the maximum current rating of 2 Amps. Therefore, the rheostat can be connected to the circuit with a voltage of 70V.

2. Voltage of 100V: - Using Ohm's Law again: I = V / R - I = 100V / 40 Ohms = 2.5 Amps - The current flowing through the rheostat is 2.5 Amps, which exceeds the maximum current rating of 2 Amps. Therefore, the rheostat should not be connected to the circuit with a voltage of 100V.

In summary, the rheostat with a resistance of 40 Ohms and a maximum current of 2 Amps can be safely connected to a circuit with a voltage of 70V, but it should not be connected to a circuit with a voltage of 100V as it exceeds the maximum current rating.