1. [-/4 Points] DETAILS SERPSE10 30.1.OP.002. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A magnetic field is uniform over a flat, horizontal circular region with a radius of 1.90 mm, and the field varies with time. Initially the field is zero and then changes to 1.50 T, pointing upward when viewed from above, perpendicular to the circular plane, in a time of 125 ms. (a) What is the average induced emf around the border of the circular region? (Enter the magnitude in UV and the direction as seen from above.) magnitude direction ---Select--- Jas seen from above (b) Immediately after this, in the next 70.0 ms, the magnetic field changes to a magnitude of 0.500 T, pointing downward when viewed from above. What is the average induced emf around the border of the circular region over this time period? (Enter the magnitude in UV and the direction as seen from above.) magnitude direction -Select--- as seen from above Need Help? Read It Submit Answer 2. [-/1 Points] DETAILS SERPSE10 30.1.OP.003. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A 24-turn circular coil of wire has diameter 1.05 m. It is placed with its axis along the direction of the Earth's magnetic field of 56.0 T and then in 0.200 s is flipped 180. An average emf of what magnitude is generated in the coil? mV Need Help? Read It Watch It Submit Answer 3. [-/1 Points] DETAILS SERPSE10 30.1.OP.004. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The figure below displays a circular loop of aluminum wire in a uniform magnetic field pointing into the page. The radius of the loop is 10.0 cm and the magnitude of the field is 0.110 T. You grab points A and B and pull them in opposite directions, stretching the loop until its area is nearly zero, taking a time of 0.180 s to do so. What is the magnitude of the average induced emf in the loop (in mV) during this time? x x * xx A x x x x x x x x x x B xx x x 4. [-/1 Points] DETAILS SERPSE10 30.1.OP.007. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A 38-turn circular coil of radius 3.00 cm and resistance 1.00 2 is placed in a magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies in time according to the expression B = 0.010 0 + 0.040 Or, where B is in teslas and t is in seconds. Calculate the induced emf in the coil at t = 4.80 s. mV Need Help? Read It Submit Answer mV Need Help? Read It Watch It Submit Answer 5. [-/1 Points] DETAILS SERPSE10 30.2.OP.014. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER In the figure below, a steel bar sitting on two parallel metal rails, connected to each other by a resistor, is pulled to the right at a constant speed. The resistance R = 4.00 Q, the distance between the rails is { = 1.20 m, and a uniform 3.30 T magnetic field is directed into the page. At what speed (in m/s) should the bar be moved to produce a current of 0.500 A in the resistor? m/s Need Help? Read It Submit Answer app 6. [-/2 Points] DETAILS SERPSE10 30.2.OP.015.MI. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The figure below shows a top view of a bar that can slide on two frictionless rails. The resistor is R = 6.20 02, and a 2.50-T magnetic field is directed perpendicularly downward, into the page. Let f = 1.20 m. R xxx x xxxxxx x x * * 20 x XX xxx x xxx x xx x x * app x (a) Calculate the applied force required to move the bar to the right at a constant speed of 2.50 m/s. N (to the right) (b) At what rate is energy delivered to the resistor? W Need Help? Read It Master It Submit Answer 7. [-16 Points] DETAILS SERPSE10 30.2.OP.016. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER In the figure below, a steel bar sitting on two parallel metal rails, connected to each other by a resistor, is pulled to the right with a constant force of magnitude Fapp = 1.30 N. The friction between the bar and rails is negligible. The resistance R = 8.00 Q, the bar is moving at a constant speed of 1.75 m/s, the distance between the rails is {, and a uniform magnetic field B is directed into the page. app (a) What is the current through the resistor (in A)? A (b) If the magnitude of the magnetic field is 3.00 T, what is the length {(in m)? m (c) What is the rate at which energy is delivered to the resistor (in W)? w (d) What is the mechanical power delivered by the applied constant force (in W)? W What If? Suppose the magnetic field has an initial value of 3.00 T at time t = 0 and increases at a constant rate of 0.500 T/s. The bar starts at an initial position x = 0.100 m to the right of the resistor at t = 0, and again moves at a constant speed of 1.75 m/s. Derive time-varying expressions for the following quantities. (e) the current through the 8.00 resistor R (Use the following as necessary: t. Assume I(t) is in A and t is in s. Do not include units in your answer.) I(t) = A (f) the magnitude of the applied force F app required to keep the bar moving at a constant speed (Use the following as necessary: t. Assume Fapp(t) is in N and t is in s. Do not include units in your answer.) N Fapp(t) Need Help? Read It Submit Answer