Question

1) Two resistors are connected to each other in parallel, one resistor has a known value of R, the resistance of the second one is unknown. If the equivalent of two resistors in parallel is equal to what is the resistance of the second one? R A)R B) 2R C) DI E) 4R 2) Which one of the following sentences is correct about the velocity selector? A) The velocity of charged particles leaving a velocity selector are the same for all particles independent value of charge and value of mass. B) Velocity of a charged particle leaving a velocity selector is equal to v = B/E C) The velocity of a charge leaving the selector is independent of electric field. D) A velocity selector is made up of magnetic field and electric field which are parallel with respect to each other. E) The velocity of charge leaving the selector is independent of the magnetic field. 3) A charged particle is moving with velocity of Vin a magnetic field of B, which one of the followings is correct: A) The direction of force F on the charge is parallel to magnetic field B B) The direction of force F on the charge is parallel to velocity direction V C) The force is maximized when velocity direction and magnetic field are parallel D) The force Fis perpendicular (normal) to both velocity Vand magnetic field B E) The direction of force on positive charge or negative charge would be the same

please do 2 and 3 . ignore 1