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

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
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1 Answer

Answer :

(a) Both are likely to be concave.
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Related questions

2. The radius of curvature of a spherical mirror is 20 cm. What is its focal length? -Physics-10

Description : 2. The radius of curvature of a spherical mirror is 20 cm. What is its focal length? -Physics-10

Last Answer : Radius of curvature (R) = 20 cm Radius of curvature of the spherical mirror = 2 × Focal length (f) R = 2f f= R/2 = 20 / 2 = 10 Therefore, the focal length of the spherical mirror is 10 cm.

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

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.

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

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.

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

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.

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

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.

1. Find the focal length of a convex mirror whose radius of curvature is 32 cm. -Physics-10

Description : 1. Find the focal length of a convex mirror whose radius of curvature is 32 cm. -Physics-10

Last Answer : Radius of curvature (R) = 32 cm Radius of curvature = 2 × Focal length (f) R= 2f f = R/2 = 32/2 = 16 Therefore, the focal length of the given convex mirror is 16 cm.

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

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.

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

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.

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

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.

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

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

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

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.

2. A concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located? -Physics-10

Description : 2. A concave mirror produces three times magnified (enlarged) real image of an object placed at 10 cm in front of it. Where is the image located? -Physics-10

Last Answer : Magnification produced by a spherical mirror: Object distance (u) = – 10 cm v = 3 × (- 10) = – 30 cm Therefore, the negative sign indicates that an inverted image is formed in front of the given concave mirror at a distance of 30 cm.

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

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

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

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,

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

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.

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

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.

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

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.

4. Why do we prefer a convex mirror as a rear-view mirror in vehicles? -Physics-10

Description : 4. Why do we prefer a convex mirror as a rear-view mirror in vehicles? -Physics-10

Last Answer : Convex mirror is preferred as a rear-view mirror in cars and vehicles as it gives a wider field of view, which helps the driver to see most of the traffic behind him. Convex mirrors always form an erect, virtual, and diminished image of the objects placed in front of it.

3. Name the mirror that can give an erect and enlarged image of an object. -Physics-10

Description : 3. Name the mirror that can give an erect and enlarged image of an object. -Physics-10

Last Answer : The mirror that can give an erect and enlarged image of an object is Concave Mirror.

1. Define the principal focus of a concave mirror. -Physics-10

Description : 1. Define the principal focus of a concave mirror. -Physics-10

Last Answer : Light rays that are parallel to the principal axis of a concave mirror converge at a specific point on its principal axis after reflecting from the mirror. This point is called the principal focus of the concave mirror.

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

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.

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

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

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

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

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

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.

A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed. -Physics

Description : A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed. -Physics

Last Answer : Answer. I hope it helped you.

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

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

A concave lens focal length 10 cm is placed on the axis of concave mirror of 10 cm radius at a distance of 5 cm from the mirror. An object is placed s

Description : A concave lens focal length 10 cm is placed on the axis of concave mirror of 10 cm radius at a distance of 5 cm from the mirror. An object is placed s

Last Answer : A concave lens focal length 10 cm is placed on the axis of concave mirror of 10 cm radius ... the object itself. Determine the position of the object.

A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20 cm away from the lens? What would be the size of the image formed if the object is 2 cm high? With the help of a ray diagram show the formation of the image by the lens in this case. -Physics

Description : A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20 cm away from the lens? What would be the size of ... ? With the help of a ray diagram show the formation of the image by the lens in this case. -Physics

Last Answer : This is the Answe:

An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens. -Physics

Description : An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens. -Physics

Last Answer : The focal length' of convex length is 7.14 cm. Solution: The given quantities are Height of the object h = 50 cm Height of the image formed h' = -20 cm Image distance v = 10 cm The image ... object distance will be So the focal length will be Thus the focal length of the convex lens is 7.14 cm

An object 2 cm high is placed at a distance of 64 cm from a white screen. On placing a convex lens at a distance of 32 cm from the object it is found that a distinct image of the object is formed on the screen. What is the focal length of the convex lens and size of the image formed on the screen? Draw a ray diagram to show the formation of the image in this position of the object with respect to the lens. -Physics

Description : An object 2 cm high is placed at a distance of 64 cm from a white screen. On placing a convex lens at a distance of 32 cm from the object it is found that a distinct image of the object ... diagram to show the formation of the image in this position of the object with respect to the lens. -Physics

Last Answer : Since, object-screen distance is double of object-lens separation, the object is at a distance of 2f from the lens and the image should be of the same size of the object.

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

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

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

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.

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

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.

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

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.

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

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.

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

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.

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

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.

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

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.

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

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.

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

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.

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

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

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

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.

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

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.

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

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

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

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.

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

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

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

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

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

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

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

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.

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

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.

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

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.