Midterm 1
Circuit section AB absorbs energy at a rate of 50 W when current i = 1.0 A through it is in the indicated direction. Resistance R = 2.0 Ω. (a) What is the potential difference between A and B? Emf device X lacks internal resistance. (b) What is its emf? (c) Is point B connected to the positive terminal of X or to the negative terminal?
What is (a)50V (b)48V (c) negative?
The figure represents a snapshot of the velocity vectors of three electrons near a wire carrying
current i. The three velocities (𝑣1, 𝑣2, 𝑣3) have the same magnitude; their directions are shown
by the arrows in the figure. Electrons 1 and 2 are located at the same distance from the wire,
electron 3 is the closest to the wire. Which of the following statements is true? (1 or more
correct answers)
A. Electron 3 experiences the greatest magnetic force.
B. The direction of the magnetic field generated by current 𝑖 points into the page at the location of all three electrons.
C. The magnetic force on electron 1 points downward.
D. The magnetic force on electron 2 points to the left.
What is B and C?
The figure shows three situations in which identical circular conducting loops are in piece-wise uniform magnetic fields that are either increasing (Inc) or decreasing (Dec) in magnitude at identical rates. In each, the dashed line coincides with a diameter. Rank the situations according to the magnitude of the current induced in the loops.
A. a > b = c
B. a = b > c
C. a = b = c
D. a < b = c
What is a=b>c?
Electric flux of closed surface with -3.0μC on the inside of the surface and -6.0μC on the outside of the surface?
What is I_E=3.4x10^5 Nm^2/C
Two metal objects in Fig. 25-24 have net charges of +100 nC and −100 nC, which result in a 50 V potential difference between them. (a) What is the capacitance of the system? (b) If the charges are changed to +200 nC and −200 nC, what does the capacitance become? (c) What does the potential difference become?
What is (a) 2.0nF, (b) 2.0nF, and (c) 100 V?
The radius of the cylindrical long straight wire is a = 0.01 m, and the wire carries a current 𝑖 = 1 𝐴 that is distributed uniformly over its cross-section. a) What’s the magnitude of the current density in the wire? Find the magnetic field b) inside (r=0.005 m) and c) outside (R=0.02 m) the wire.
What is (a) 3183.1 A/m^2, (b)98.7 uT, and (c) 98.7uT?
In the circuit below, the battery has an emf 𝜀 = 1.0 𝑉 and 𝑅 = 1.0 Ω. It’s switched to a for a long time, and then at 𝑡 = 0𝑠, we switch the connection from a to b. At 𝑡 = 10𝑠, the current is half of the current at 𝑡 = 0𝑠 after switching to b.
a) What’s the time constant of the RL circuit?
b) What’s the inductance L?
What is (a) 14.43s? and (b)14.4H?
Net electric field of point O if q1=2μC and is 8cm to the left of point O, q2=-3μC and is 8 cm to the right of point O, and q3=-5.0μC and is 8cm above point O.
What is Enet=7.02x10^6 N/C i_hat +7.02x10^6N/C j_hat?
A block in the shape of a rectangular solid has a cross-sectional area of 3.50 cm2 across its width, a front-to-rear length of 15.8 cm, and a resistance of 935 Ω. The block’s material contains 5.33 × 1022 conduction electrons/m3. A potential difference of 35.8 V is maintained between its front and rear faces. (a) What is the current in the block? (b) If the current density is uniform, what is its magnitude? What are (c) the drift velocity of the conduction electrons and (d) the magnitude of the electric field in the block?
What is (a)38.3 mA (b)109.4 A/m2 or 109.4 1/(ohms-meters),(c)1.28x10-2 m/s or 1.28cm/s, and (d)227N/C or 227 V/m?
In the figure, a particle moves along a circle in a region of uniform magnetic field of magnitude B = 4.00 mT. The particle is either a proton or an electron (you must decide which). It experiences a magnetic force of magnitude 3.20 × 10^−15 N. What are (a) the particle’s speed, (b) the radius of the circle, and (c) the period of the motion? (mass of a proton is 1.67 × 10^−27 kg, mass of electron 9.11 × 10^-31 kg, charge of particle is 1.6 ×10^-19 C)
What is (a) 5 M m/s, (b) 13.05m, and (c)16.4us?
Two long, straight wires are separated by 0.120 m. The wires carry currents of 8.0 A in opposite
directions, as the drawing indicates. Find the magnitude of the net magnetic field at the points
labeled (a) A and (b) B. (c) What’s the magnitude of the magnetic force per unit length between the
two wires? (d) Is the magnetic force between the two wires attractive or repulsive?
What is (a) 43 uT, (b)53 uT, (c) 1.07*10^-4 N/m, (d) repulsive?
Magnitude and direction of the electrostatic force on charge 1 if on the x-axis, charge 2 is -4.0μC and 0.2m to the left of charge 1, charge 1 is 3.0μC, and charge 3 is -7.0μC and 0.15m to the right of charge 1.
What is 5.69N i_hat?
What is the potential of a conducting sphere of radius 0.11 m whose uniform surface charge density is 18.5 nC/m2 (with V = 0 at infinity)? (𝜖0 = 8.854 C2/Nm2)
What is 230 V?