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Chrged Particle in Magnetic Field. House Wiring.

1. A magnetic field can change the direction of motion of a charged particle yet in doing so it has done no work on the particle. Why? Give another example of a force causing an object to change direction without doing any work on it.
2. Explain why it takes more fuel for a spacecraft to travel to the Moon from Earth than it takes to travel from the Moon to the Earth.
3. In my last house, when I used to put the electric kettle on in the kitchen at the same time as the washing machine was on in the laundry and the electric heater was on in the lounge room the fuse would blow and all the appliances would stop working. Why did it do this? Explain using circuit diagrams.

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Q 1
Work is done when the point of application of force moves in the direction of force. No work is done if the force and displacement are perpendicular to each other.
If a charged particle, with charge q, is projected in a magnetic field B with speed v, it has a force of magnitude Bev acting on it that is perpendicular to the plane containing v and B.
Since, displacement of the particle is in the direction of velocity v and force is ...

Solution Summary

No work done by force acting on charged particle moving in magnetic field.
Why more work is done by space craft going to moon than space craft coming from moon to earth.
Why does fuse blow when many appliances work together from household mains ?