Upcoming SlideShare
×

# Ohm's law (group 3) ppt

1,870 views

Published on

1 Like
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

Views
Total views
1,870
On SlideShare
0
From Embeds
0
Number of Embeds
5
Actions
Shares
0
90
0
Likes
1
Embeds 0
No embeds

No notes for slide
• CBSE Science of Xth -> Chapter 12 : Electricity -> 12.4 OHM’S LAW (page no :203)
• CBSE Science of Xth -> Chapter 12 : Electricity -> 12.4 OHM’S LAW (page no :203)
• CBSE Science of Xth -> Chapter 12 : Electricity -> 12.4 OHM’S LAW (page no :203)
• ### Ohm's law (group 3) ppt

1. 1. ` Good Hope English Medium School Group 3 (Avogadros) Class : X Presented
2. 2. Members of Group 3 (Avogadros)  Vijay Das P  Adish Assäin  Akhila Aniyan  Renna Jan  Fathima Hiba  Sherin K Lal
3. 3. Ohm’s Law
4. 4. Georg SimonOhm Ohm, who was born at Erlangen in Germany, seems to have acquired his interest in science from his father, a skilled mechanic. Georg Simon Ohm, was a German physicist, best known for his “Ohm’s Law”. The physical unit of electrical resistance, the Ohm, was named after him. He studied at the University of Erlangen and then taught at the Cologne Polytechnic in 1817.
5. 5. He was working on the manuscript of his textbook on optics when he died on July 6, 1854. Ohm also worked on sound, suggesting in 1843 that the ear analyzes complex sounds into a combination of pure tones. This result was rediscovered by Hermann von Helmholtz in 1860. He achieved his lifelong dream, a position with a major university, in 1849 as professor at the University of Munich.
6. 6.  Current flow through an ideal conductor is directly proportional to the potential difference (voltage) and inversely proportional to the resistance. Conductor is also known as a resistor. An ideal conductor is a material whose resistance does not change with temperature. For an ohmic device,     Voltage Current Resistance V I R V = Voltage I = Current (Amperes = A) R = Resistance (Ohms = Ω) Ohm’s Law
7. 7.  Conventional Current: (the current in electrical circuits) Flow of current from positive terminal to the negative terminal. - has units of Amperes (A) and is measured using ammeters.  Voltage: Energy required to move a charge from one point to another. - has units of Volts (V) and is measured using voltmeters. Current and Voltage Defined
8. 8. Metals obey Ohm’s Law linearly so long as their temperature is held constant. Their resistance values do not fluctuate with temperature, i.e. the resistance for each resistor is a constant Most ohmic resistors will behave non-linearly outside of a given range of temperature, pressure, etc. Ohmic Resistors
9. 9. Voltage and Current Relationship for Linear Resistors Voltage versus Current for a 10 ohm Resistor 0 0.1 0.2 0.3 0.4 0.5 0.6 0 1 2 3 4 5 6 Voltage (V) Current(A) Voltage and current are linear when resistance is held constant.
10. 10. Ohm’s Law continued
11. 11. The total resistance of a circuit is dependant on the number of resistors in the circuit and their configuration 1 2 1 2 ... 1 1 1 1 ...         total total R R R R R R R R Series Circuit Parallel Circuit Ohm’s Law continued
12. 12. Series Circuit Current is constant Why? Because only one path for the current to take 1 2 3 1 2 3 1 2 3          V V V V I I I I R R R R V I R
13. 13.   1 1 2 2 3 3 1 2 3 1 2 3 1 2 3 1 2 3                         V I R V I R V I R R R R R V V V V V I R I R I R V I R R R V I R Series Equivalent Circuit
14. 14. 1 2 3 1 2 3 1 23 23 2 3 1 2 3 where 1 1 1 1              V V V V I I I I I I I I I R R R R Voltage is constant Why? Because there are 3 closed loops in the circuit  V I R Parallel Circuit
15. 15. Parallel Equivalent Circuits   231 2 3 2 3 1 23 123 1 2 3 123 1 23 1 2 3 1 2 3 1 2 3 1 2 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1                                  let so and R R R R R R R R R R R R I I I I R R R R I I I V I R I I I R R R R R R
16. 16. Now you get to try some experiments of your own, but first, a quick tutorial on the equipment you will be using You’re turn to do some experiments!
17. 17. - Voltmeter - Ammeter - Breadboard - Potential Divider - Resistors - 9V battery Let’s do a quick review… The equipments you’ll be using:
18. 18. Voltmeter: Connect either end of the meter to each side of the resistor If you are reading a negative value, you have the probes switched. There should be no continuity beeping. If you hear beeping, STOP what you are doing and ask someone for help! How to use a voltmeter:
19. 19. Voltmeter
20. 20. Voltage: Probes connect to either side of the resistor Measuring Voltage
21. 21. You encountered breadboards early in the year. Let’s review them: Breadboards The breadboard How the holes on the top of the board are connected:
22. 22. Series Resistors are connected such that the current can only take one path
23. 23. Parallel Resistors are connected such that the current can take multiple paths
24. 24. Experiment 1 – Ohm’s Law Click on the black box to watch the vi
25. 25. In reality, the data we get is not the same as what we get in theory. Why? Because when we calculate numbers in theory, we are dealing with an ideal system. In reality there are sources of error in every aspect, which make our numbers imperfect. Real data
26. 26. Conclusion Ohmic resistors obey Ohm’s Law linearly Resistance is affected by temperature. The resistance of a conductor increases as its temperature increases. V I R 
27. 27. Thank You for Watching! 