1. State the principle of an electric generator. -Physics-10

1 Answer

Answer :

Electric generator works on the principle of electromagnetic induction. In a generator, electricity is generated by rotating a coil in the magnetic field.

Related questions

Description : 2. What is the principle of an electric motor? -Physics-10

Last Answer : The working principle of electric motor is based on the magnetic effect of current. A current carrying conductor when placed in a magnetic field experiences force and rotates. The direction of the rotation of the conductor can be determined by Fleming’s Left hand rule.

Description : 4. The essential difference between an AC generator and a DC generator is that -Physics-10

Last Answer : AC generator has slip rings while the DC generator has a commutator. AC generators have two rings known as the slip rings while DC generators have two half rings known as the commutator. This is main difference between AC generator and DC generator.

Description : 3. The device used for producing electric current is called a -Physics-10

Last Answer : generator The device used for producing electric current is known as generator. Generator converts mechanical energy to electric energy.

Description : 3. What precaution should be taken to avoid the overloading of domestic electric circuits? -Physics-10

Last Answer : A few of the precautions to be taken to avoid the overloading of domestic electric circuits are as follows: Connecting too many devices to a single socket should be avoided Using too many appliances at the same time should be avoided Faulty appliances should not be connected to the circuit

Description : 2. An electric oven of 2 kW power rating is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain. -Physics-10

Last Answer : The current drawn by the electric oven can be calculated using the formula P = V × I I = P/V Substituting the values, we get I = 2000 W/220 V = 9.09 A The current drawn by the electric oven is 9.09 A which exceeds the safe limit of the circuit. This causes the fuse to melt and break the circuit.

Description : 1. Name two safety measures commonly used in electric circuits and appliances. -Physics-10

Last Answer : The safety measured commonly used in electric circuits are as follows: Fuse Each circuit should be connected to a fuse because a fuse prevents the flow of excessive current through the circuit. ... to the ground by earthing and the people using the appliance is prevented from getting electrocuted.

Description : 3. What is the role of split ring in an electric motor? -Physics-10

Last Answer : Split ring plays the role of commutator in an electric motor. The commutator reverses the direction of the current flowing through the coil after each half rotation of the coil. Due to this reversal of current, the coil continues to rotate in the same direction.

Description : What does OHM's law state? -Physics-10

Last Answer : Ohm's Law given by Georg Ohm states that, at constant temperature, the Potential Difference is directly proportional to the Electric Current. Formula: V = IR

Description : 6. State whether the following statements are true or false. -Physics-10

Last Answer : False An electric motor converts electrical energy into mechanical energy. b. True An electric generator is a device that generates electricity by rotating a coil in a magnetic field. c. True A long ... lines. d. False Live wires have red insulation cover while the earth wire has green insulation.

Description : 1. State Fleming’s left-hand rule. -Physics-10

Last Answer : Fleming’s Left hand rule states that if we arrange our thumb, forefinger and middle finger of the left hand at right angles to each other, then the thumb points towards the ... points towards the direction of magnetic field and the middle finger points towards the direction of current.

Description : 9. When is the force experienced by a current–carrying conductor placed in a magnetic field largest? -Physics-10

Last Answer : When the direction of the current is perpendicular to the direction of the magnetic field is when the force experienced is the largest.

Description : 8. How does a solenoid behave like a magnet? Can you determine the north and south poles of a current–carrying solenoid with the help of a bar magnet? Explain. -Physics-10

Last Answer : A solenoid is a long coil of circular loops of insulated copper wire. The magnetic field produced around the solenoid when the current is passed through it is similar to the magnetic field ... shows the arrangement of magnetic fields produced around the solenoid when current is passed through it.

Description : 7. List two methods of producing magnetic fields. -Physics-10

Last Answer : Following are the methods of producing magnetic fields: By using a permanent magnet we can produce magnetic field and it can be visualized by spreading iron fillings on a white paper and keeping a ... conductors such as solenoid and circular loop can be used to see the presence of magnetic field.

Description : At the time of short circuit, the current in the circuit reduces substantially. does not change. increases heavily. vary continuously. -Physics-10

Last Answer : increases heavily When two naked wires in the circuit come in contact with each other, the amount of current flowing in the circuit increase abruptly resulting in short circuit.

Description : 2. The phenomenon of electromagnetic induction is -Physics-10

Last Answer : producing induced current in a coil due to relative motion between a magnet and the coil. The phenomenon of inducing current in a coil due to the relative motion between the coil and the magnet Is known as electromagnetic induction.

Description : 1. Which of the following correctly describes the magnetic field near a long straight wire? -Physics-10

Last Answer : The field consists of concentric circles centered on the wire. The magnetic field near a long straight wire are concentric circles. Their centers lie on the wire.

Description : A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each -Physics-10

Last Answer : half revolution When a rectangular coil is rotated in magnetic field, the direction of the induced current changes once in half revolution. As a result, the direction of the current in the coil remains the same. In text 13.7 Page:238

Description : 3. Which sources produce alternating current? -Physics-10

Last Answer : Power plants and AC generators are some of the sources that produce alternating current.

Description : 2. Name some sources of direct current. -Physics-10

Last Answer : DC generator and cell are some sources of direct current.

Description : 1. Explain different ways to induce current in a coil. -Physics-10

Last Answer : Following are the different ways to induce current in a coil: If the coil is moved rapidly between the two poles of horse shoe magnet, electric current is induced in the coil. When a magnet is moved relative to the coil, an electric current is induced in the coil.

Description : 3. A positively-charged particle (alpha-particle) projected towards the west is deflected towards north by a magnetic field. The direction of magnetic field is -Physics-10

Last Answer : The direction of the magnetic field can be determined using the Fleming’s Left hand rule. According to the rule, if we arrange our thumb, forefinger and the middle finger of the left ... north, hence the direction of magnetic field will be upward according to Fleming’s Left hand rule.

Description : 2. In Activity 13.7, how do we think the displacement of rod AB will be affected if (i) current in rod AB is increased; (ii) a stronger horse-shoe magnet is used; and (iii) length of the rod AB is increased? -Physics-10

Last Answer : A current carrying conductor when placed in a magnetic field experiences force. The magnitude of this force will increase with the increase in the amount of current, length of conductor and the strength ... AB is increased Stronger horse shoe magnet is used When the length of the rod AB increases

Description : 1. Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.) -Physics-10

Last Answer : Solution: (c) and (d) When a proton enters the region of magnetic field, it experiences magnetic force. Due to which the path of the proton becomes circular. As a result, the velocity and the momentum change.

Description : The magnetic field inside a long straight solenoid-carrying current -Physics-10

Last Answer : d. is the same at all points The magnetic field inside a long straight current carrying solenoid is uniform therefore it is the same at all points.

Description : 2. The magnetic field in a given region is uniform. Draw a diagram to represent it. -Physics-10

Last Answer : Solution: hope this is helpul

Description : 1. Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop. -Physics-10

Last Answer : Solution: For the downward direction of the current, the direction of the magnetic field will be as if emerging from the table outside the loop and merging with the table inside the loop. Similarly, ... the table outside the loop and merging with the table inside the loop, as shown in the figure.

Description : 1. Draw magnetic field lines around a bar magnet. -Physics-10

Last Answer : Magnetic field lines of a bar magnet emerge from the North Pole and terminate at the South Pole as shown in the figure below.

Description : 1. Why does a compass needle get deflected when brought near a bar magnet? -Physics-10

Last Answer : The compass needle is a small magnet. When the compass needle is brought close to a bar magnet, the magnetic field lines of the compass needle interact with the magnetic field lines of bar magnet, which causes the compass needle to deflect.

Description : 17. A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging? -Physics-10

Last Answer : Power of lens (P) = 1/f P = 1.5D f = 1/1.5 = 10/15 = 0.66 m A convex lens has a positive focal length. Therefore, it is a convex lens or a converging lens.

Description : 16. Find the focal length of a lens of power -2.0 D. What type of lens is this? -Physics-10

Last Answer : Power of lens (P) = 1/f P = -2D f = -1/2 = -0.5 m A concave lens has a negative focal length. Therefore, it is a concave lens.

Description : 15. An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharply focused image can be obtained? Find the size and nature of the image. -Physics-10

Last Answer : Object distance (u) = – 27 cm Object height (h) = 7 cm Focal length (f) = – 18 cm According to the mirror formula, The negative value of image height indicates that the image formed is inverted.

Description : 14. An object 5 cm is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position, nature and size of the image. -Physics-10

Last Answer : Object distance (u) = - 20 cm Object height (h) = 5 cm Radius of curvature (R) = 30 cm Radius of curvature = 2 Focal length R = 2f f = 15 cm According to the mirror formula, ... image height indicates that the image formed is erect. Hence, the image formed is erect, virtual, and smaller in size.

Description : 13. The magnification produced by a plane mirror is +1. What does this mean? -Physics-10

Last Answer : The positive sign means an image formed by a plane mirror is virtual and erect. Since the magnification is 1 it means that the size of the image is equal to the size of the object.

Description : 12. An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image. -Physics-10

Last Answer : Focal length of convex mirror (f) = +15 cm Object distance (u) = - 10 cm According to the mirror formula, The image is located at a distance of 6 cm from the mirror on the other ... and a value of less than 1 of magnification indicates that the image formed is virtual and erect and diminished.

Description : 11. A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens? Draw the ray diagram. -Physics-10

Last Answer : Focal length of concave lens (OF1), f = – 15 cm Image distance, v= – 10 cm According to the lens formula, The negative value of u indicates that the object is placed 30 cm in front of the lens. This is shown in the following ray diagram.

Description : 10. An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed. -Physics-10

Last Answer : Height of the Object, h0 = 5 cm Distance of the object from converging lens, u = -25 cm Focal length of a converging lens, f = 10 cm Using lens formula, Thus, the image is inverted and formed at a distance of 16.7 cm behind the lens and measures 3.3 cm. The ray diagram is shown below.

Description : 9. One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations. -Physics-10

Last Answer : Yes, it will produce a complete image of the object, as shown in the figure. This can be verified experimentally by observing the image of a distant object like a tree on a screen when the ... the lens is covered with a black paper. However, the intensity or brightness of the image will reduce.

Description : 8. Name the type of mirror used in the following situations. -Physics-10

Last Answer : Concave Mirror: Because concave mirrors can produce a powerful parallel beam of light when the light source is placed at their principal focus. (b) Convex Mirror: Because of its largest field of view. (c) Concave Mirror: Because it concentrates the parallel rays of the sun at a principal focus.

Description : We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? -Physics-10

Last Answer : Range of the distance of the object = 0 to 15 cm from the pole of the mirror. Nature of the image = virtual, erect, and larger than the object.

Description : 5. No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be -Physics-10

Last Answer : (d) The mirrors are likely to be either plane or convex

Description : 4. A spherical mirror and a thin spherical lens have a focal length of -15 cm. The mirror and the lens are likely to be -Physics-10

Last Answer : (a) Both are likely to be concave.

Description : 3. Where should an object be placed in front of a convex lens to get a real image of the size of the object? -Physics-10

Last Answer : (b) The object should be placed at twice the focal length

Description : 2. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object? -Physics-10

Last Answer : (d) The position of the object should be between the pole of the mirror and its principal focus.

Description : 1. Which one of the following materials cannot be used to make a lens? -Physics-10

Last Answer : (d) Clay cannot be used to make a lens because if the lens is made up of clay the light rays cannot pass through it

Description : 3. Find the power of a concave lens of focal length 2 m. -Physics-10

Last Answer : Focal length of concave lens (f) = 2 m Power of lens (P) = 1/f = 1/ (-2) = -0.5D

Description : 2. A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? -Physics-10

Last Answer : The position of the image should be at 2F since the image is the real and same size. It is given that the image of the needle is formed at a distance of 50 cm from the convex lens. Therefore, the needle is ... (u) = - 50 cm Image distance, (v) = 50 cm Focal length = f According to the lens formula,

Description : 1. Define 1 dioptre of power of a lens. -Physics-10

Last Answer : Dioptre is the SI unit of power of lens is denoted by the letter D. 1 dioptre can be defined as the power of a lens of focal length 1 metre.

Description : 5. The refractive index of diamond is 2.42. What is the meaning of this statement? -Physics-10

Last Answer : Diamond has a refractive index of 2.42 which means that the speed of light in diamond will reduce by a factor of 2.42 as compared to its speed in the air. In other words, the speed of light in diamond is 1/2.42 times the speed of light in vacuum.

Description : 4. You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table. -Physics-10

Last Answer : Light travel faster in water as compared to kerosene & turpentine as the refractive index of water is lower than that of kerosene and turpentine. The speed of light is inversely proportional to the refractive index.

Description : 3. Find out, from Table, the medium having highest optical density. Also find the medium with lowest optical density. -Physics-10

Last Answer : Lowest optical density = Air Highest optical density = Diamond The optical density of a medium is directly related to its refractive index. A medium with the highest refractive index will have the ... index. Hence, air has the lowest optical density and diamond has the highest optical density.