If 4.0

A person wants to catch the bus. Standing on the side of the street, the person sees the bus, 150 meters to the left appraoching at 24.6 m/s. The bus stop is located 50 meters to the right. Already, the bus is slowing-down at 1.45 m/s^2 so the person immediately begins jogging towards the bus stop at a constant 3.12 m/s. (a) Which one gets to the stop first, (b) how long must it wait for the other, and (c) where does the bus pass the person?

(a) Describe the expected detector spectrum of 160Co given by a MultiChannel Analyser.

(b) Calculate the energy difference between the photopeak and the Compton edge.

(c) Calculate the position of the backscatter peak.

a.) Suppose that there is a constant magnetic field in the xy-plane with magnitude 0.5 T, and a proton is moving with a speed of 3 × 10^5 m/s at a 45◦ angle relative to the field. What is the magnitude of the acceleration of the proton assuming it only experiences the force due to the magnetic field?

b.) Inside of any microwave, there is a tube called a magnetron in which electrons orbit an approximately constant magnetic field. The electrons in the microwave complete 2.4 billion circular orbits every second, and this causes them to emit microwave radiation having a frequency of 2.4 GHz. What is the strength (magnitude) of the magnetic field inside of the magnetron?

c.) A long, straight wire carrying a 3 A current perpendicular to the xy-plane intersects the x-axis at x = −2 cm. Another straight wire carrying a 3 A current perpendicular to the xy-plane intersects the x-axis at x = 2 cm. At what point(s) along the x-axis is the magnetic field zero if the two currents are in the opposite direction? If there are no such points, write “None” and show your reasoning.

d.) Suppose that a stream of electrons is moving along a straight wire perpendicular to this page, and the stream is moving into the page. We take the page to be in the xy-plane, and we suppose that the wire along which the electrons are moving intersects the page at the origin. A proton is at point (x,y) = (0 cm, 3 cm) and has velocity (vx, vy) = (5×10^4 m/s, 0 m/s). Will the proton’s path curve into the page, out of the page, or will it just keep moving straight with its current velocity? Write either “into,” “out,” or “straight” in the answer box, and explain your reasoning.

A Ferris Wheel, starting from rest, undergoes a constant angular acceleration of 0.033 rad/s2 to get to its final operating angular velocity of 0.24 rad/s. (a) How long does it take the Ferris Wheel to get to its operating angular velocity? (b) How many revolutions does it make during this time interval?

A block of mass m is pressed against a light spring by a distance d and is kept at rest (Fig. 1). The spring, of elastic constant k, is released and the block is thrown on a horizontal surface without friction. The smooth surface curves upward and the block rises. Calculate your speed when you have climbed a height h. (Express v as a function of k, m, d, h and g). 

State Babinet’s theorem; and use Huygens’s principle to prove it.

How can I contribute to science / the science community?

It should be stream-of-conciousness writing from the heart. 5 minutes of reflective journaling should result in an essay of about 150-200 words.

1. Explain on the basic operation of the n-channel JFET. Draw the drain characteristics or output characteristics of the mentioned JFET type and denote the important parameters on the graph

2. Explain why the JFET is called a unipolar device. Your explanation must be based on the n-channel or p-channel device which is biased to operate as an amplifier

3. A JFET amplifier has a load resistance, RL= 500 kΩ. Find the ac drain resistance, rd if the amplification factor, μ and voltage gain, Av of the amplifier are 24 and 20 respectively

4. (i) What are the functions of MOSFET in electronic devices?
(ii)Why the N-channel MOSFET is considered better than the p-channel MOSFET
(ii) How does the MOSFET differ than the JFET?
(iii) Explain the basic operations of n-channel DMOSFET and EMOSFET
(iv) What does it mean “the channel is pinched off” in MOSFET

5. Design an operational amplifier with no change in output sign and voltage gain = 10 (Given Rin = 3 Ω and Vin = 5V)

Calculate the Fourier Series of the function below. Results should be in full, closed-form series. Graph using Octave or Matlab to compare and check answer. Period is 2pi.

f(x)= 1 for -pi<x<-pi/2, -1 for -pi-2<x<0, 0 for 0<x<pi

Consider an object of mass

m₁ = 0.360 kg

moving with a uniform speed of 5.40 m/s on a frictionless surface. This object makes an elastic head-on collision with another object of mass

m₂ = 0.645 kg

which is initially at rest.

(a) Find the speed of m₁ immediately after collision. m/s

(b) Find the speed of m₂ immediately after collision m/s

only Answer part 4,5 and 6 of this question, thank you !

A -4.00 nC point charge is at the origin, and a second -6.00 nC point charge is on the x-axis at x=0.800 m .

1-Find the electric field (magnitude and direction) at point on the x-axis at x = 0.200 m. Answer is ( E_x=-749 N/C)

2- Find the electric field (magnitude and direction) at point on the x-axis at x = 1.20 m. Answer is (E_x= -362 N/c)

3- Find the electric field (magnitude and direction) at point on the x-axis at x = -0.200 m. Answer is (E_x=953 N/c)

4- Find the net electric force that the two charges would exert on an electron placed at point on the x-axis at x = 0.200 m. F_{x=( )}

5- Find the net electric force that the two charges would exert on an electron placed at point on the x-axis at x = 1.20 m. F_{x=(    )}

6- Find the net electric force that the two charges would exert on an electron placed at point on the x-axis at x = -0.200 m. F_{x=( )}

An electron moves in crossed electric and magnetic fields on a spiral (helical) trajectory. What are the values of the respective magnetic and electric fields, so that the radius of a helix is 10cm, and its a pitch (vertical height of one complete helix turn) is 1 cm. Hint: approximate the motion as a circular motion is XY only due to magnetic field and motion in Z direction only due to electric field.

An electron moves in crossed electric and magnetic fields on a spiral (helical) trajectory. What are the values of the respective magnetic and electric fields, so that the radius of a helix is 1 cm , its a pitch (vertical height of one complete helix turn) is 10 cm and initial kinetic energy of the electron was 3 keV (kilo electron-volts). Hint: approximate the motion as a circular motion is XY only due to magnetic field and motion in Z direction only due to electric field.

A 0.200 kg ball starting from rest rolls down an inclined plane with θ=30°.

a)Find the acceleration of the ball, and the magnitude of normal force exerted by the plane.

b) If it starts from rest a height h = 30.0 cm above its position at the bottom of the incline (measured between the center of the ball at each position), what is the speed of the ball vf at that bottom point, and how long did it take to get there?