Ohm S Law Examples With Answers

In national 5 physics calculate the resistance for combinations of resistors in series and parallel.

Ohm s law examples with answers. We need two points from the graph to find the slope. R 3 v i 3 99 2 10 1 9 ohm. For example 250 ma is 0 25 a. The simplest example of ohm s law is an old fashioned dimmer switch in your house.

But this time we don t know the voltage of the battery. I 12 v 600 ohm i 0 02 a 20 ma milli ampere so the current in the circuit is 20 ma. Based on the table the relationship between v i and r is the value of r inversely proportional to v and i. The current i flowing through a conductor is directly proportional to the potential difference i e.

For example if you measure the current in milliamps which you usually will in electronic circuits you must convert the milliamps to amperes by dividing by 1 000. Temperature strain etc do not change. Color coding technique is used to represent the values of resistors in the form of colored bands. The current flowing through a conductor is directly proportional to the applied voltage provided the temperature of the conductor remains constant it specifically refers to.

If you don t like calculating things yourself check out this calculator for ohm s law. 2 the r s on the right hand side of the equation cancel. Use ohms law to relate resistance current and voltage. According to ohm s law the value of v i must be constant.

Voltage v across its ends provided the physical conditions i e. That means the larger the v and i the smaller r. 3 i is then left in terms of v and r. The most important thing to remember about ohm s law is that you must always do the calculations in terms of volts amperes and ohms.

4 5 or 6 bands are designed over the bodies of resistors. Hence in the graph of v against i given above the slope of the graph is the resistance. Ohm s law quiz mcqs with resistor color coding technique. This relationship is called ohm s law and be stated as.

1 since v voltage and r resistance are known solve for i current by dividing both sides of the equation by r. As you turn the dimmer switch up the light gradually brightens until it reaches full intensity. Let us try another example. 4 substitute in the values for v voltage and r resistance.