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CBSE PMT – 2007 SCREENING PHYSICS 7. In the following circuit, the output Y for all
1. The primary and secondary coil of a transformer have 50 and 1500 turns respectively. If the magnetic flux φ linked with the primary coil is given by φ = φ0 + 4t, where φ is in webers, t is time in seconds and φ0 is a constant, the output voltage across the secondary coil is (a) 120 volts (b) 220 volts (c) 30 volts (d) 90 volts A beam of electron passes undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons move (a) in a circular orbit (b) along a parabolic path (c) along a straight line (d) in an elliptical orbit. The position x of a particle with respect to time t along x-axis is given by x = 9t2 – t3 where x is in metres and t in second. What will be the position of this particle when it achieves maximum speed along the +ve x direction? (a) 54 m (b) 81 m (c) 24 m (d) 32 m. A particle starting from the origin (0, 0) moves in a straight line in the (x, y) plane. Its coordinates at a later time are ( 3,3) . The path of the particle makes with the x-axis an angle of (a) 45o (b) 60o (c) 0o (d) 30o A car moves from X to Y with a uniform speed vu and returns to Y with a uniform speed vd. The average speed for this round trip is (a) v u vd
possible inputs A and B is expressed by the truth table
A B
A Y B
(a) A B Y (b) A B Y 011 001 011 010 101 100 110 110 (c) A B Y (d) A B Y 000 000 011 010 101 100 111 111 In a radioactive decay process, the negatively charged emitted β -particles are (a) the electrons produced as a result of the decay of neutrons inside the nucleus (b) the electrons produced as a result of collisions between atoms (c) the electrons orbiting around the nucleus (d) the electrons present inside the nucleus. The phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is (b) 0.707 π (a) π
1. The primary and secondary coil of a transformer have 50 and 1500 turns respectively. If the magnetic flux φ linked with the primary coil is given by φ = φ0 + 4t, where φ is in webers, t is time in seconds and φ0 is a constant, the output voltage across the secondary coil is (a) 120 volts (b) 220 volts (c) 30 volts (d) 90 volts A beam of electron passes undeflected through mutually perpendicular electric and magnetic fields. If the electric field is switched off, and the same magnetic field is maintained, the electrons move (a) in a circular orbit (b) along a parabolic path (c) along a straight line (d) in an elliptical orbit. The position x of a particle with respect to time t along x-axis is given by x = 9t2 – t3 where x is in metres and t in second. What will be the position of this particle when it achieves maximum speed along the +ve x direction? (a) 54 m (b) 81 m (c) 24 m (d) 32 m. A particle starting from the origin (0, 0) moves in a straight line in the (x, y) plane. Its coordinates at a later time are ( 3,3) . The path of the particle makes with the x-axis an angle of (a) 45o (b) 60o (c) 0o (d) 30o A car moves from X to Y with a uniform speed vu and returns to Y with a uniform speed vd. The average speed for this round trip is (a) v u vd
possible inputs A and B is expressed by the truth table
A B
A Y B
(a) A B Y (b) A B Y 011 001 011 010 101 100 110 110 (c) A B Y (d) A B Y 000 000 011 010 101 100 111 111 In a radioactive decay process, the negatively charged emitted β -particles are (a) the electrons produced as a result of the decay of neutrons inside the nucleus (b) the electrons produced as a result of collisions between atoms (c) the electrons orbiting around the nucleus (d) the electrons present inside the nucleus. The phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is (b) 0.707 π (a) π