Multiple Choice Questions : Physics Class X |
MAGNETIC EFFECTS OF ELECTRIC CURRENT |
1.A magnetic field can exert force on |
(a)a moving magnet (b) stationary magnet (c) moving charge (d)all of these |
2.Magnetic lines of force |
(a)have more directions (b)have no physical reality |
(c)can be used to indicate the direction of the magnetic field of a point |
(d)all the above |
3. When is the back emf of an electric motor the greatest? |
(a)when the motor is witched on |
(b)when the motor is speeding up |
(c)when the motor is at maximum speed |
(d)when the motor is slowing down |
4.According to international convention of color coding in a wire |
(a)live is red, neutral is black and earth is green |
(b) live is brown, neutral is blue and earth is green |
(c) live is brown, neutral is green and earth is black |
(d)live is red, neutral is yellow and earth is blue |
5.An electric current can be produced in a closed loop |
(a)by connecting it to a battery, but not by moving a magnet near it |
(b)by moving a magnet near it, but not by connecting it to a battery |
(c)by connecting it to a battery, as well as by moving a magnet near it |
(d)neither by connecting it to battery nor by moving a magnet near it |
6.Which of the following describes the common domestic power supplied in India? |
(a)220V,100Hz (b)110V,100Hz |
(c)220V,50Hz (d)110V,50Hz |
7.Magnetic field due to a current carrying straight wire depends on |
(a)current only (b)distance from the wire only |
(c) both a) and (b) (d)none |
8.The direction of the magnetic field produced by a current carrying straight conductor can be found using |
(a)right hand thumb rule (b)right hand Fleming’s rule |
(c)left hand Fleming’s rule (d)right hand screw rule |
9.A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each |
(a)two revolution (b)one revolution (c)half revolution (d)one-forth revolution |
10.Electric motor |
(a)is based on electromagnetic induction (b)converts kinetic energy into electrical energy |
(c)converts electric energy into kinetic energy (d)none |
11.To convert ac generator into dc generator |
(a)split ring type commentator must be used (b)slip rings and brushes must be used |
(c)a stronger magnetic field has to be used (d)a rectangular wire loop has to be used |
12.Choose the incorrect statement |
(a)The direction of magnetic field at a point is taken to be the direction in which north pole of magnetic compass needle points |
(b)magnetic field lines are closed curves |
(c)If magnetic field lines are parallel and equi distant, they represent zero field strength |
(d)relative strength of magnetic field is shown by the degree of closeness of the field lines. |
13.Force on a current conductor in a magnetic field depends on |
(a)length of the conductor (b)current in the conductor |
(c)magnitude of the magnetic field (d)all of these |
14.Magnetic field inside a solenoid is |
(a)non-uniform (b)circular |
(c)uniform (d)none |
15.Magnetic field lines due to a bar magnet is similar to that of a |
(a)current carrying straight wire (b) solenoid (c) two parallel wires (d)none |
Class 09 Atoms and Molecules Numerical Problem based on Law of chemical Combination Law of conservation of mass Law of constant proportion Empirical formula 1. If 10 grams of CaCO 3 on heating gave 4.4g of CO 2 and 5.6g of CaO, show that these observations are in agreement with the law of conservation of mass.(Based on Law of conservation of mass) Solution: Mass of the reactants = 10g ; Mass of the products = 4.4 + 6.6g = 10g Since the mass of the reactants is equal to the mass of the products, the observations are in agreement with the law of conservation of mass. 2. 1.375 g of cupric oxide was reduced by heating and the weight of copper that remained was 1.098g. In another experiment 1.179 g of copper was dissolved in nitric acid and the resulting copper nitrate was converted into cupric oxide by ignition . The weight of cupric oxide formed was 1.476 g. which law of chemical combinations does this data state? Solution: in first experiment: Copper oxide = 1....
Comments
Post a Comment