# Ohm's law - practice problems

Ohm's law states that the current through a conductor (or resistor) between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, it arrives at the usual mathematical equation I = U/R or I=V/RDirection: Solve each problem carefully and show your solution in each item.

#### Number of problems found: 102

- Heat energy

Energy is measured using the unit Joule (J). Temperature is measured using the unit degree Celsius °C). To increase the temperature of 1 liter of water by 1°C, 4200 J of heat energy is required. (a) Kelly wants to increase the temperature of 2 liters of w - Transformer 3

A 200/115 V transformer has an LV (Low voltage) side resistance of 0.06 Ohm. What is the resistance referred to HV side (high voltage)? - Resistance 82714

A load of 23.5 ohm is connected to an ideal voltage source of 30V, and a current of 1.2A passes through the circuit. Determine the magnitude of the source's internal resistance and the short-circuit current. - Corresponds 82534

A current of 0.1 A can lethally affect a human body with a resistance of 3 kΩ. What voltage corresponds to this current?

- Resistance 82533

A current of 275 mA passes through the filament of a light bulb with a resistance of 800 Ω. What voltage is the bulb connected to? - Lighting-650W 82356

In the office will be connected: computer 800W, kettle 2.5KW, lighting-650W, oven 1.9KW; electric stove 3.3KW; air conditioning 6100W. As the smallest cross-section of the cables, we have to bring them to this room. Recalculate for Copper and Aluminum wir - Appliance 82079

The voltage at the terminals of the appliance is 4.5 V. A current of 0.5A passes through the appliance. What voltage must the appliance have if a current of 0.7A is to pass through it? - Resistance 81503

What is the value of the resistance of the rectifier diode in the forward direction if the current IF = 5 A flows through it and the voltage between the anode UF = 820 mV? - Resistor 81502

How big a series resistor do we need to connect to the LED if a voltage drop of 3.2 V is to be created on it and a current of 16 mA flows through the diode? We want to connect the diode to a voltage of 5V.

- Several resistors

We have a box with the same resistors, so all of them have a resistance value of 200 ohms. Draw the connection of several resistors so that the resulting resistance is: a) 100 b) 120 (only 4 resistors) - Resistances 80706

The current I = 4A branches into three wires with resistances R1 = 2Ώ, R2 = 5Ώ, R3 = 10Ώ. Calculate the total resistance of the connection and the voltage of the source. How big are the currents in each wire? - Automatically 80704

The electric circuit breaker automatically switches off the circuit of the 220 V electrical network at a current of 6 A. Determine the maximum power in the protected circuit. - Consumption 80702

A current of 500 mA passed through the filament of a light bulb with a resistance of 400 ohms. What is the consumption of a light bulb in 5 hours? - Resistance 80700

Determine the largest voltage on a resistor with a resistance of 150 ohms if the largest permitted electrical power current in the resistor is 2 W.

- Resistance 80699

The immersion cooker plate has data 220 V, 300 W. What is the resistance of the heating wire? - Resistance 80698

The electric iron plate has written 220 V, 1200 W. What is the resistance of the heating wire? - Resistance 80606

How much resistance must be connected in parallel with the 1-ohm resistor to make the total resistance 0.6 ohm? - A charge

A charge of 9 C passes through series-connected resistors with resistances of 40 ohms and 60 ohms in 1 minute. a) What voltage are they connected to? b) Calculate the voltage across each resistor. - Resistances 80604

Resistors with resistances of 6 ohms and 10 ohms are connected in series to a voltage of 24 V. a) How much current passes through them? b) What are the voltages on the individual resistors?

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