3) An ideal parallel-plate capacitor consists of a set of two parallel plates of area separated by a very small distance When the capacitor plates carry A d. charges +Q and -Q, the capacitor stores energy If the separation between the plates is doubled, how much electrical energy is stored in the capacitor? U0. A) 4U0 B) 2U0 C) U0 D) U0/2 E) U0/4 4) Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. The electric charge of each of the three particles is, respectively, A) 1 is neutral, 2 is negative, and 3 is positive. B) 1 is neutral, 2 is positive, and 3 is negative. C) 1 is positive, 2 is neutral, and 3 is negative. D) 1 is positive, 2 is negative, and 3 is neutral. E) 1 is negative, 2 is neutral, and 3 is positive. 5) An electron traveling toward the north with speed 4.0 × 105 m/s enters a region where the Earth's magnetic field has the magnitude 5.0 × 10-5 T and is directed downward at 45° below horizontal. What is the magnitude of the force that the Earth's magnetic field exerts on the electron? (e = 1.60 × 10-19 C) A) 2.3 × 10-18 N B) 3.2 × 10-18 N C) 2.3 × 10-19 N D) 3.2 × 10-19 N E) 2.3 × 10-20 N 6. A long wire carries an electric current into the page. What is the direction of the magnetic field due to the current, north of the wire? N north east
3) An ideal parallel-plate capacitor consists of a set of two parallel plates of area A separated by a very small distance d. When the capacitor plates carry charges +Q and -Q, the capacitor stores energy U0. If the separation between the plates is doubled, how much electrical energy is stored in the capacitor? A) 4U0 B) 2U0 C) U0 D) U0/2 E) U0/4 4) Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. The electric charge of each of the three particles is, respectively, A) 1 is neutral, 2 is negative, and 3 is positive. B) 1 is neutral, 2 is positive, and 3 is negative. C) 1 is positive, 2 is neutral, and 3 is negative. D) 1 is positive, 2 is negative, and 3 is neutral. E) 1 is negative, 2 is neutral, and 3 is positive. 5) An electron traveling toward the north with speed 4.0 × 105 m/s enters a region where the Earth's magnetic field has the magnitude 5.0 × 10-5 T and is directed downward at 45° below horizontal. What is the magnitude of the force that the Earth's magnetic field exerts on the electron? (e = 1.60 × 10-19 C) A) 2.3 × 10-18 N B) 3.2 × 10-18 N C) 2.3 × 10-19 N D) 3.2 × 10-19 N E) 2.3 × 10-20 N 6. A long wire carries an electric current into the page. What is the direction of the magnetic field due to the current, north of the wire? N north east
Physics%201220%20Test%202.docx