Question
please write out your work so I can understand what you did. I'll have the final correct answers tomorrow and I use this site often and ALWAYS rate! thanks in advance!
1)
2)
3)
A uniform magnetic field of magnitude 0.80 T in the negative z-direction is present in a region of space, as shown in the figure. A uniform electric field is also presem. An electron that is projected with an initial velocity v0 = 9.1 times 104 nVs in the positive .t-direction passes through the region without deflection. What is the electric field in the region (magnitude AND direction)? Hint: We need the net force in both the y-direction and z-direction to be zero. There is one force due to the magnetic field and a second force due to the electric field. So what docs the electric field have to be to produce a force that will cancel out the force from the magnetic field? As shown in the figure, a wire and a 10-Ohm resistor are used to form a circuit in the shape of a square. 20 cm by 20 cm. A uniform but no steady magnetic field is directed into the plane of the circuit. The magnitude of the magnetic field is decreased from 1.50 T to 0.50 T in a time interval of 63 ms. What is the current induced in the wire and in which direction does it travel through the resistor? A heat engine performs the reversible cycle abca with 9.0 moles of an ideal gas. as shown in the figure. Path ca is an adiabatic process. The temperatures at points a and b are 300 K and 500 K. respectively. The volume at point c is 0.20 m3. The adiabatic constant of the gas is 1.60. C v=(5/3) mR=(5/3 )NkB. Cp=(8/3)nR=(8/3)NkB. What is the thermal efficiency of the engine?
Explanation / Answer
1)B = 0.8 T
v = 9.1*10^4 m/s
when electric force is equal to magnetic force it does not deflect.
q*E = q*v*B
E = v*B = 9.1*10^4*0.8 = 7.28*10^4 N/C
here the magneitc force acts in down ward direction.
so, electric force should act in upward.
so, electric field should be downward. since electron has negative cherge i
electric force acts in the oposite direction of electric field.
2) R = 10 ohm
A = 0.2*0.2 = 4*10^-2 m^2
B1 = 1.5T and B2 = 0.5 T
t = 63*10^-3 s
emf = A*(B2-B1)/t = 4*10^-2*(0.5-1.5)/63*10^-3 = 0.635 volts
i = emf/R = 0.635/10 = 0.0635 A = 63.5 mA
according lenz's law current flows in clockwise direction.
