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Wednesday, March 24, 2010

Block test

It's never too late to discover what you did not know.
1. The negative charge experiences a force in a direction opp to the direction of E.
2. If the force is opp to motion , it will slow the particle , hence decelerate or acceleration is negative.
3. The loss in KE will give rise to increase in EPE. Or WD against electric force will give increase in EPE. Note : If you find this statement hard to understand , replace this electron with a stone being thrown upwards and replace the electric with gravitational.
4. The constant force means that the electric field strength E is constant
5. The increase in EPE is also QV where V is the potential difference. Equating increase in EPE(also decrease in KE = initial KE - final KE ) with QV gives V= 160 (not 35) V . But the potential is zero at final destination . Hence at the start the potential is 160 V . Note also : Positive charge moves from high to low potential but negative moves from low to high potential when released at rest(WD by electric force) .
Again you can device a way with gravity. When a stone moves against its weight its height increases. But a negative charge is a anti stone. Replace the word height with potential decreases and stone to anti stone.
Goodluck . Takes time to internalise. Be true because science is truth.