# magnetism , physics

i need this in 1 and half hours most

Week 3 â€“
Magnetism and Induction
Please solve the following problems. You must show all work for full/partial credit. When complete, attach a typed cover sheet and submit to the assignment drop-box.
1) If a charge particle move in a straight line and there no other forces on it except possibly from a magnetic field, can you say with certainty that no magnetic field is present? Explain.
2) In a velocity selector, the uniform magnetic field of 1.5 T is produced by a large magnet. Two parallel plates with a separation of 1.5 cm produce the perpendicular electric field. What voltage should be applied across the plates so that:
a) A singly ionized ion traveling 8.0 x 104 m/s will pass through undeflected.
b) A double ionized ion traveling at the same speed will pass through undeflected.
3) A horizontal magnetic field of 1.0 x 10-4 T is at an angle of 30o to the direction of the current in a straight wire 75 cm long. If the wire carries a current of 15 A, what is the magnitude of the force on the wire?
4) An electron travels at a speed of 2.0 x 10-4 m/s through a uniform magnetic field of strength 1.2 x 10-3 T. What is the magnitude of the magnetic force on the electron if its velocity and the magnetic field:
a) Are perpendicular
b) Make an angle of 45o
c) Are parallel
d) Are exactly opposite?
5) A square loop of wire with sides of length 40 cm is in a uniform magnetic field perpendicular to its area If the fieldâ€™s strength is 100 mT an it decays to zero in 0.010 seconds:
a) What is the magnitude and of the average emf induced in the loop?
b) What happens to the emf is the side lengths are reduced by a factor of Â½?
6) The armature of an ac generator has 100 turns. Each turn is a rectangular loop measuring 8.0 cm by 12 cm. The generator has a sinusoidal voltage output with an amplitude of 24 V. If the magnetic field of the generator is 250 mT,
a) With what frequency does the armature turn?
b) If you double the B and cut   in half, how does this affect the amplitude?
7) An ac generator supplies 20 A at 440 V to a 10,000 V power line. If the step up transformer has 150 turns in its primary coil, how many turns are in the secondary coil?
Week 4 â€“
Electromagnetic Waves and Light
Please solve the following problems. You must show all work for full/partial credit. When complete, attach a typed cover sheet and submit to the assignment drop-box.
1) An antenna is connected to a car battery. Will the antenna emit electromagnetic radiation? Why or why not? Explain.
2) A light-year is a measure of distance (not time). How many meters does light travel in a year?
3) How long does it take a laser beam to travel to the Moon and back? Take the Earth Moon distance to 384,000 km.
4) A beam of light is incident on a plane mirror at an angle of 35o. If the mirror rotates through a small angle  through what angle will the reflected ray rotate?
5) The speed of light in polythene is 1.99 x 108 m/s What is the index of refraction of polythene?
6) A beam of light with red and blue components of wavelengths 670 nm and 425 nm, respectively, strikes a slab of fused quartz at an incident angle of 30o. On refraction, the different components are separated by an angle of 0.001312 rad. If the index of refractions of the red light is 1.4925, what is the index of refraction of the blue light?