Physics current electricity help?

Question

guys please help me with these questions

1. what are the consequences of substituting for a blown fuse another

a) with a higher current rating
b)with a lower current rating

2. would accidental contact with a live wire in a mains-operated appliance necessarily be fatal? explain

3a) what would be the current in your body if you touched the terminals of a 12 v battery, if the contact R was 100 000 ohms?

3b) if your skin became wet, and the contact resistance dropped to only 1000 ohms, what would be the current in your body? is this current potentially dangerous? explain.

4. In a powerpoint correctly wired, the switch and fuse are in the 'active' line. if a power point is wired incorrectly with the netrual and active lines connected the wrong way . a toaster with a metal case is plugged into that power point. what is the effect of incorrect wiring

a) will the toaster still work? b) switch? c) if person turns off toaster and uses knife to remove bread. safe?xplain all

Answer 1

If the new fuse is too big and the short that blew the old one happens again, you could send more current through the circuit than it's designed for and burn the house down.
If the new fuse is too small, it could blow during normal operation.

Touching 240VAC probably won't kill you if you're not wet, but I wouldn't bet your life on it.

12V at 100,000 ohms would deliver 12/100ma.

At 1000 ohms you'd get 12ma. Enough to make you say a bad word, but not enough to kill you.

The toaster probably wouldn't know it since the neutral line shouldn't be connected to the case. If some halfwit grounded the toaster to what was supposed to be the neutral line and you touched it while touching ground somewhere, better have your insurance paid up.

People get shocked using knives to clear a toaster because the stuck bread is keeping the mechanism down, or you push it down with the knife, so the heating elements are still live. Just unplug the thing.

Answer 2

ability distinction is given via equation V=I*R because R*=a million.0*10^5 ohm/m it follows that interior the gap of three cm = 0.03 m the resistance is R=a million.0*10^5 ohm/m * 0.03 m = 3 * 10 ^3 ohm So V=1200 A * 3 * 10 ^3 ohm = 3.6 * 10 ^6 Volt