1.What is the strength (in V/m) of the electric field between two parallel conducting plates separated by 4.00 cm and having a potential difference (voltage) between them of 2.95 ✕ 10^4 V? 2. How far...

Physics questions


1.What is the strength (in V/m) of the electric field between two parallel conducting plates separated by 4.00 cm and having a potential difference (voltage) between them of 2.95 ✕ 10^4 V? 2. How far apart (in m) are two conducting plates that have an electric field strength of 2.50 ✕ 10^3 V/m between them, if their potential difference is 13.5 kV? 3. The voltage across a membrane forming a cell wall is 82.0 mV and the membrane is 9.40 nm thick. What is the electric field strength in volts per meter? (The value is surprisingly large, but correct. Membranes are discussed later in the textbook.) You may assume a uniform E-field. 4. Find the maximum potential difference (in kV) between two parallel conducting plates separated by 0.789 cm of air, given the maximum sustainable electric field strength in air to be 3.0 ✕ 10^6 V/m. 5. A 0.710 cm diameter plastic sphere, used in a static electricity demonstration, has a uniformly distributed 80.0 pC charge on its surface. What is the potential (in V) near its surface? 6. What are the sign and magnitude in coulombs of a point charge that produces a potential of -4.00 V at a distance of 3.00 mm? 7. An electrostatic paint sprayer has a 0.100 m diameter metal sphere at a potential of 30.0 kV that repels paint droplets onto a grounded object. (a)What charge (in C) is on the sphere? (b)What charge (in C) must a 0.200 mg drop of paint have to arrive at the object with a speed of 10.0 m/s? 8. A parallel plate capacitor has metal plates, each of area 1.15 m^2, separated by 1.90 mm. What charge (in µC) is stored in this capacitor if a voltage of 2.60 ✕ 10^3 V is applied to it? 9. In open heart surgery a much smaller amount of energy will defibrillate the heart. (a)What voltage (in kV) is applied to the 7.00 µF capacitor of a heart defibrillator that stores 35.0 J of energy? (b)Find the amount (in mC) of stored charge. 10 A nervous physicist worries that the two metal shelves of his wood frame bookcase might obtain a high voltage if charged by static electricity, perhaps produced by friction. (a) What is the capacitance (in F) of the empty shelves if they have area 2.60 ✕ 10^−1 m^2 and are 0.280 m apart? (b) What is the voltage between them (in V) if opposite charges of magnitude 2.20 nC are placed on them? (c)To show that this voltage poses a small hazard, calculate the energy stored (in J).