Ncert – class 10- science – Chapter 12 – Magnetic Effects of Electric Current 2 Welcome to your Ncert - class 10- science - Chapter 12 – Magnetic Effects of Electric Current 2 1. A DC current flows through a vertical wire in the downward direction. For an observer looking at the wire, the direction of magnetic field at a point between him and the wire is: Upward To the left Downward To the right None 2. Household appliances are usually not connected in series because: Switching off an appliance would switch off the rest A fuse would blow as soon as one appliance is used The appliances would get damaged due to high current Power consumption would be very much greater None 3. A length of wire carries a steady current. It is bent first to form a circular plane coil of one turn. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre caused by the same current is Unaltered Quarter of its first value Four times of its first value Half of its first value None 4. Which of the following electrical devices works on the principle of electro-magnetic induction ? Electric cooker Electric bulb L.E.D. Electric fan None 5. As a negatively charged bowling ball rolls eastward toward some bowling pins, in what direction does it experience a force, due to the earth's magnetic field (Assume the earth's field is pointing straight north)? Down East South North None 6. What is a commutator? A device that reverses the direction of flow of voltage through a circuit is called a commutator. All of these A device that flows in the direction of flow of current through a circuit is called a commutator. A device that reverses the direction of flow of current through a circuit is called a commutator. None 7. Current is flowing through a conductor and creates a magnetic field. Assume that this is the only source of the magnetic field. Reversing a current in a straight conductor with no change to the magnitude(ampere value) will cause a _________. Reversal and reduction of the magnetic field Disappearance of the magnetic field Reversal of the direction of the magnetic field Reduction in the magnetic field None 8. The magnetic field around a current-carrying coil lasts Till its half-life period For three hours As long as current flows through it Field is permanent None 9. None 10. Which one of the following statements best describes the nature of the field lines due to a bar magnet? Field lines are continuous lines passing inside and outside the magnet. Only one field line passes through a point Field lines start from the north pole and end on the south pole. Any number of field lines can pass through a point Field lines start from the north pole and end on the south pole. Only one field line passes through a point Field lines are continuous lines passing inside and outside the magnet. Any number of field lines can pass through a point None 11. Why is the switch for any electrical appliance always fitted on to the live wire ? The device can never be switched off if the switch is in the neutral lead. No current flows in the neutral wire. There will be a short circuit if the switch is in the earth lead. The device can only be isolated if the switch is in the live lead None 12. In a circular current-carrying conductor, if the current flows in the clockwise direction, the magnetic field direction is __________. Perpendicular to the plane of the coil away from the observer Parallel to the plane of the coil away from the observer Parallel to the coil towards the observer Perpendicular to the plane of the coil towards the observer None 13. In alternating current: The direction of current changes constantly The direction of current is always positive The direction of current is always negative None of these None 14. A straight wire carries conventional current toward the sky.What is the direction of the magnetic field due to the current at a point west of the wire? North West South East None 15. The phenomenon of producing an emf in a circuit whenever the magnetic flux linked with a coil changes is ................................ Inducing current Change in current Electro-magnetic induction Inducing voltage None 16. A charge particle is moving in the direction of a magnetic field.The magnetic force acting on the particle: is zero is in the direction of its velocity is in the direction opposite to its velocity is perpendicular to its velocity None 17. Consider an experiment where Electric current is flowing in a wire. It is observed that clockwise magnetic field is produced around the wire. A teacher decides to reverse the direction of source battery which results in reversal of electrical current. What will be the effect on magnetic field? None of the above Direction of field lines reverse Magnetic field disappears Field lines changes direction to parallel to wire None 18. The magnetic field around a current carrying coil Lasts for three hours Lasts as long as current flows through it Is permanent Lasts till its half-life period None 19. A soft bar is inserted inside a current carrying solenoid. The magnetic field inside the solenoid. Will decrease Will remain the same Will become zero Will incresae None 20. A beam of protons is moving horizontally towards you. As it approaches you, it passes through a magnetic field which is directed upwards. As you see it, the magnetic field will deflect the beam to the: Bottom Top Left Right None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
