What Is Resistance In Electricity Class 7

Similar to friction it can be measuredrbyresistance v dividing r voltage by the current.

What is resistance in electricity class 7.

Variables affecting electrical resistance. The resistance of an object is affected by several factors. If you sit in a tree and the wind blows hard you can resist falling down by clinging to the branches. A wire made of a material having high electrical.

Resistance when an electric current flows through a circuit there will be some resistance that opposes it. Electrical resistance is also known as specific electrical resistance. The resistance to the flow of charge in an electric circuit is analogous to the frictional effects between water and the pipe surfaces as well as the resistance offered by obstacles that are present in its path. Copper and aluminium metals have very low electrical resistance whereas alloys such as nichrome have very high electrical resistance nichrome is an alloy of nickel chromium iron and manganese.

I v voltage i current 36. Copper wire has a low resistance to electricity flow whereas plastic wire has a high resistance. 2 magnetic effect and 3 chemical effect. The reciprocal quantity is electrical conductance and is the ease with which an electric current passes.

Following is the formula of electrical resistivity. The resistance is measured in units of ohms ω. The flow of charge through wires is often compared to the flow of water through pipes. The si unit of electrical resistivity is ohms metre.

The resistance is measured in uni. Because electricity flows easily through copper wire copper is a good conductor of electricity. Resistance is an electrical quantity that measures how the device or material reduces the electric current flow through it. Mention the name of the two devices that work on the basis of magnetic effects of current.

Electric current and its effects class 7 extra questions science chapter 14 electric current and its effects class 7 science extra questions very short answer type questions. Electric resistivity is defined as the electrical resistance offered per unit length and unit cross sectional area at a specific temperature and is denoted by ρ. To resist something means to try to prevent it. Resistance is an electrical quantity that measures how the device or material reduces the electric current flow through it.

E in electronics and electromagnetism the electrical resistance of an object is a measure of its opposition to the flow of electric current. Electrical resistance shares some conceptual parallels with the notion of mechanical friction. If we make an analogy to water flow in pipes the resistance is bigger when the pipe is thinner so the water flow is decreased.