Electricity and Magnetism Answers

For dominant mode propagation in TE mode, if the rectangular

waveguide has a broader dimension of 31.14 mm , then the cutoff

wave number:

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1. When a 12.0-V car battery powers a single 30.0 W headlight, how many electrons pass through it each second?

2. Two electrons are 10^5 m apart. One electron is fixed on its position. The other, originally at rest, is released. How fast is the free electron moving when it is 10^ −3 m from the fixed charge? Apply conservation of energy.

3. Two point charges, +400 uC and -2.00 uC are 0.55m apart. (a) what is the potential energy of the pair? (b) If the positive charge is fixed and the other is released from rest, how far from each other should the charges be if the negative charge is moving with a speed of 2.30 x 10^2 m/s? Let the mass of the moving charge be 8.00 x 10^−6 kg.

1. A proton (charge +𝑒=1.602 𝑥 10^−19 𝐶) moves a distance d = 0.30 m in a straight line between points a and b in a linear accelerator. The electric field is uniform along this line, with magnitude 𝐸= 2.1 𝑥 10^7 𝑁/𝐶 in the direction from a to b. Determine: (a) the force on the proton; (b) the work done on it by the field; (c) the potential difference

2. What is the potential difference between two point in an electric field if it takes 500J of energy to move a charge of 2.5C between these two points?

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1. Two charges of 𝑞1=+ 12.0 𝑛𝐶 and 𝑞2=− 12.0 𝑛𝐶 are 0.100 m apart (such pairs of point charges with equal magnitude and opposite sign are called electric dipoles.). Calculate the electric field caused by 𝑞1.

2. Two charges of 𝑞1=+ 3.0 𝑛𝐶 and 𝑞2=− 7.0 𝑛𝐶 are separated by a distance of 50 cm. What is the electric field strength at a point that is 20cm from 𝑞1 and 30cm from 𝑞2? The point lies between 𝑞1 and 𝑞2.

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1. Two charges, of 𝑞1=+ 3.50 𝑝𝐶 and 𝑞2=− 4.50 𝑝𝐶 are 0.400 m apart. Where along the line joining them will net electric field be zero? Note: 𝐸⃗ 𝑛𝑒𝑡= 0 and 𝐸⃗ 1 and 𝐸⃗ 2 are opposite.

2. Four point charges are positioned as such: A(0,1), B(2,1), C(0,0), D(2,0). Charge A = -3 microcoulombs, Charge B = 3 microcoulombs, C = 2 microcoulombs, and D = -2 microcoulombs. What is the net electric field experienced at the origin.

1. A solenoid consists of 200 turns of wire and has a length of 0.15m. What is the magnetic field inside

the solenoid if the current through it is a.) 0.24A, b.) 0.50A and c.) 1.2A

2. A circular wire loop with an area, A = 0.1m² , is placed in magnetic field of magnitude B = 0.25 T.

Calculate the magnetic flux through the loop when a.) the plane of the loop is perpendicular to the field,

and b.) the normal plane of the loop makes an angle of 30⁰ with respect to the field.

A square cost of resistance 4ohm ,50 turns and side length 5cm is places with it's plane making on amgle of 40° with a uniform field 2T.In 4.5 s the coil rotates until it's plane becomes parallel to the.magnetic field.Find the current induced in the coil.

A magnetic field of 3.2T is perpendicular to a square coil of 12 turns.The length of each side of the coil is 9cm.Find the magnetic flux through the coil if the magnetic field makes an angle of 30° with the normal to the plane of the coil.

True or false the number of coils and the number of batteries are factors that can affect the strength of an

Electromagnet

A copper wire is 2.50 m long and has a diameter of 2.5 mm. How much current will it draw when connected to a 3.0 V source?