draw the ray diagram of refraction of light at curved surfaces the following rarer medium to denser medium
Vacuum tubes are non-ohmic devices because their resistance changes with voltage and current. This non-linearity in resistance is due to the nature of the electron flow within the vacuum tube, causing it to exhibit non-ohmic behavior.
Examples of non magnets are wood, petroleum, oxygen, etc.
A filament lamp is a non-ohmic conductor because its resistance changes with applied voltage. As the voltage increases, the resistance also increases. This is due to the temperature-dependent behavior of the filament material, which causes the resistance to vary.
Non-transparent materials do not allow light to pass through them, making them opaque. Examples include metals, wood, and ceramics. These materials absorb or reflect light rather than transmitting it.
If it has constant temperature (one can do this by dipping it in a beaker of water) it can be considered an ohmic conductor since Ohm's law states that the Voltage and amperage are directly proportional in a metallic conductor of constant temperature.
iron,gold
current doublesAnswerIt depends on whether the wire is ohmic or non-ohmic. If it is ohmic, then the current will also double. If, like tungsten, it is non-ohmic, then it depends.... because doubling the voltage will cause its resistance to increase.Ohmic materials obey Ohm's Law, whereas non-ohmic materials do not.
Ohmic (or 'linear') materials obey Ohm's Law. That is, their ratio of voltage to current remains constant for variations in voltage. Ohmic materials, therefore, produce a straight line graph when we plot current against variations in voltage;Non-ohmic (or 'non-linear') materials do not obey Ohm's Law. That is, their ratio of voltage to current variesfor variations in voltage. This means that non-ohmic materials produce a curved line graph when we plot current against variations in voltage.
non ohmic devices are diodes, LED's, Thermistors, LDR(light dependent resistors, cells in series.
no.....thermistors are not ohmic.
The main problem is that, despite its name, it is not really a 'law'! It applies to very few materials (called 'ohmic' or 'linear' materials). The vast majority of materials (called 'non-ohmic' or 'non-linear') simply do not obey Ohm's 'Law'!
which law follow non ohmic substances
ohmic conductor does obey ohm 's law. non ohmic conductor does not obey ohm's law.
A non-ohmic resistor doesn't have a constant resistance. A ohmic resistor has a constant resistance.
Vacuum tubes are non-ohmic devices because their resistance changes with voltage and current. This non-linearity in resistance is due to the nature of the electron flow within the vacuum tube, causing it to exhibit non-ohmic behavior.
Ohm's Law is by no means universal -it doesn'tapply to all materials. In fact, it doesn't apply to most materials or electrical devices! For Ohm's Law to apply, the ratio of voltage to current must remain constant for variations in voltages This is only true for 'ohmic' or 'linear' materials; those materials that do not obey Ohm's Law are called 'non-ohmic' or 'non-linear'.However, being 'non-ohmic' doesn't mean that there are noapplications for these materials! For example, a tungsten lamp filament is 'non-ohmic', but is obviously very widely used. Numerous other non-ohmic materials and devices are also widely-used, including diodes, vacuum tubes, etc.Some materials are 'non-ohmic' over for a particular range of voltage differences, then become 'ohmic' after the voltage reaches a particular value (e.g. a vacuum diode).Remember, though, that the ratio of voltage to current will always indicate the resistance for that particular combination of voltage and current, whether a material or device obeys Ohm's Law or not.Despite what most electricians think, the equation R = V/R is derived from the definition of the ohm, and has nothing whatsoever to do with Ohm's Law!
How can a filament give off heat without resistance?Another AnswerThe terms, 'ohmic' and 'non-ohmic' refer to whether or not a material obeys Ohm's Law. It has NOTHING to do with whether a filament is resistive or not!Ohmic materials obey Ohm's Law; non-ohmic materials do not.GSL incandescent lamps generally use a filament made of tungsten. If you were to apply a gradually-increasing voltage to that filament, and note the corresponding values of current and, then, plot the results in the form of a graph, you would find that the graph is a curve. For Ohm's Law to apply, the current must be proportional to voltage for variations in voltage and this is ONLY true for a straight-line graph. Tungsten, therefore, is non-ohmic and does not obey Ohm's Law.Tungsten is chosen for lamp filaments because it can withstand very high temperatures without failing. This is the main reason that it is chosen, NOT because it is non-ohmic.