Conceptual
What is unchanged in a device if the cross-sectional area through which an electric current travels is doubled?
The separation between two plates is 5.00 mm, but is reduced to 0.150 mm when a key is
pressed. The plate area is 9.5 x 10-5 m2 and the capacitor is filled with a material whose dielectric
constant is 3.50. Determine the change in capacitance detected by the computer.
What is 1.904x10-11F?
In the flashlight, the current is 0.50 A and the voltage is 6.7 V. Find (a) the power delivered to the bulb and (b) the energy dissipated in the bulb in 4.3 minutes of operation.
What is (a) 3.35W and (b) 864.3 J?
A total resistance of 3.00 Ω is to be produced by connecting an unknown resistance to a 12.0 Ω resistance. (a) What must be the value of the unknown resistance, and (b) should it be connected in series or in parallel?
What is (a)4.00 Ohms, (b) parallel
The plates of a parallel plate capacitor with a capacitance C carry a charge Q.
What is the capacitance of the capacitor if the charge is increased to 4Q, while the
geometrical and material properties are unchanged?
What is capacitance is equal to C?
The electric field in a region of space has the components Ey = Ez = 0 and Ex = (4.00 N/C)x. Point A is on the y axis at y = 3.00 m, and point B is on the x axis at x = 4.00 m. What is the potential difference VB − VA?
What is -22.5 V?
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?
A wire is 1.5 m long and 0.88 mm2 in cross-sectional area. It carries a current of 5.1 A when a 2.7 V potential difference is applied between its ends. Calculate the conductivity σ of the material of which this wire is made.
What is 3.22x106 1/ohms*meters
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?
What is the difference between capacitors in parallel and resistors in parallel?
What is capacitors in parallel have the same potential difference and are added like C1+C2+C3 while resistors have the same current and the inverse of the resistances divided by 1 added together (like 1/[(1/R1)+(1/R2)+(1/R3)]?
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?
The figure shows a circuit of four resistors that are connected to a larger circuit (I will show a picture). The graph below the circuit shows the electric potential V(x) as a function of position x along the lower branch of the circuit, through resistor 4; the potential VA is 12.0 V. The graph above the circuit shows the electric potential V(x) versus position x along the upper branch of the circuit, through resistors 1, 2, and 3; the potential differences are ΔVB = 2.00 V and ΔVC = 5.00 V. Resistor 3 has a resistance of 200 Ω. What is the resistance of (a) resistor 1 and (b) resistor 2?
What is R1=80 Ohms and R2=200 Ohms?
To obtain a current, what two things are needed?
What is power source and closed loop?
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?
When resistors are in series and one breaks what happens?
What is all of the other resistors stop working?