Exam questions from City College of New York, Exams of Physics

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Sample Exam 2 - C26-30; PHY208; 90 mins; 11/21/2023 Name & ID 1 pt: 10x1 = 10 pts 2 pts: 10 x 2 = 20 pts Total: Questions = 20 ; Points = 30 Points: 1 1) An ohmic resistor dissipates energy at a rate of 0.10 W at a voltage V. If the voltage is halved, what is the rate at which energy is dissipated (W)? A) 0.018 B) 0.40 C) 0.20 D) 0.10 E) 0.025 Points: 1 2) "The sum of the currents into a junction equals the sum of the currents out of the junction" is a consequence of: A) Newton's second law B) Ohm's law C) conservation of charge D) Newton's third law E) conservation of energy Points: 1 > > 2 3) In the formula F = qv x B: > . > . > A) v must be perpendicular to B but not necessarily to F B) all three vectors must be mutually perpendicular > > > C) F must be perpendicular to both v and B > 2 > D) F must be perpendicular to B but not necessarily to v 2 > > E) F must be perpendicular to v but not necessarily to B Points: 1 4) A uniform magnetic field is in the positive z direction. A positively charged particle is moving in the positive x direction through the field. The net force on the particle can be made zero by applying an electric field in what direction? A) Negative y B) Positive z C) Positive x D) Negative x E) Positive y