Magnification = height of the image / height of the object = v / u = 150 / 6.5 = 900 / u u = 39 cm (distance from slide to the lens). m = 23.09
1 / f = 1 / u + 1 / v = 1 /39 + 1 / 90 = 0.02564 + 0.00111 1 / f = 0.02675 (reciprocal tables)
f = 37.4 cm
Mutiso answered the question on October 15, 2018 at 18:04
-
The focal length of a converging lens is found to be 10 cm. How far should the lens be placed from an illuminated object to...
(Solved)
The focal length of a converging lens is found to be 10 cm. How far should the lens be placed from an illuminated object to obtain an image which is magnified five times on the screen?
Date posted:
October 15, 2018
.
Answers (1)
-
An object is placed 12 cm from a converging lens of focal length 18 cm. Find the position of the image
(Solved)
An object is placed 12 cm from a converging lens of focal length 18 cm. Find the position of the image
Date posted:
October 15, 2018
.
Answers (1)
-
An object 0.05 m high is placed 0.15 m in front of a convex lens of focal length 0.1 m. Find by construction, the position,...
(Solved)
An object 0.05 m high is placed 0.15 m in front of a convex lens of focal length 0.1 m. Find by construction, the position, nature and size of the image. What is the magnification?
Date posted:
October 15, 2018
.
Answers (1)
-
A horizontal pipe of cross-sectional area 50 cm2 carries water at the rate of 0.20 litres per second. Determine the speed;
a) Of the speed of...
(Solved)
A horizontal pipe of cross-sectional area 50 cm2 carries water at the rate of 0.20 litres per second. Determine the speed;
a) Of the speed of water in the pipe.
b) When the tube narrows to 20 cm2 at another point.
Date posted:
October 12, 2018
.
Answers (1)
-
Outline the equation of continuity
(Solved)
Outline the equation of continuity.
Date posted:
October 12, 2018
.
Answers (1)
-
Explain the occurrence of streamline and turbulent flow?
(Solved)
Explain the occurrence of streamline and turbulent flow?
Date posted:
October 12, 2018
.
Answers (1)
-
What is line of flow?
(Solved)
What is line of flow?
Date posted:
October 12, 2018
.
Answers (1)
-
A girl claps her hands once at a distance 250 m from a vertical cliff. If the temperature in the surrounding is 5oC, how long...
(Solved)
A girl claps her hands once at a distance 250 m from a vertical cliff. If the temperature in the surrounding is 5oC, how long does it take for her to hear the echo?
Date posted:
October 12, 2018
.
Answers (1)
-
A boy strikes a railway line (steel) with a hammer. If the speed of sound in steel is 5,200 m/s, determine the time taken for...
(Solved)
A boy strikes a railway line (steel) with a hammer. If the speed of sound in steel is 5,200 m/s, determine the time taken for the sound to reach another boy 2.3 km down the railway line with his ear on the rail.
Date posted:
October 12, 2018
.
Answers (1)
-
What are the characteristics of sound waves?
(Solved)
What are the characteristics of sound waves?
Date posted:
October 12, 2018
.
Answers (1)
-
The figure below illustrates part of the displacement-time graph of a wave travelling across water at a particular place with a velocity of 2 ms-1....
(Solved)
The figure below illustrates part of the displacement-time graph of a wave travelling across water at a particular place with a velocity of 2 ms-1. Calculate the wave’s; (a) Amplitude (b) Frequency (f) (c) Wavelength
Date posted:
October 12, 2018
.
Answers (1)
-
A rope is displaced at a frequency of 3 Hz. If the distance between two successive crests of the wave train is 0.8 m, calculate...
(Solved)
A rope is displaced at a frequency of 3 Hz. If the distance between two successive crests of the wave train is 0.8 m, calculate the speed of the waves along the rope.
Date posted:
October 12, 2018
.
Answers (1)
-
Outline the characteristics of waves
(Solved)
Outline the characteristics of waves
Date posted:
October 12, 2018
.
Answers (1)
-
Define transverse and longitudinal pulses and waves giving suitable illustrations
(Solved)
Define transverse and longitudinal pulses and waves giving suitable illustrations.
Date posted:
October 12, 2018
.
Answers (1)
-
Two identical springs, whose spring constant is 6.0 N/cm, are used to support a load of 60 N as shown below. Determine the extension of...
(Solved)
Two identical springs, whose spring constant is 6.0 N/cm, are used to support a load of 60 N as shown below. Determine the extension of each spring.
Date posted:
October 12, 2018
.
Answers (1)
-
A body of 200 g was hung from the lower end of a spring which obeys Hooke’s law. Given that the spring extended by...
(Solved)
A body of 200 g was hung from the lower end of a spring which obeys Hooke’s law. Given that the spring extended by 100 mm, what is the spring constant for this spring?
Date posted:
October 12, 2018
.
Answers (1)
-
A load of 4 N causes a certain copper wire to extend by 1.0 mm. Find the load that will cause a 3.2 mm extension...
(Solved)
A load of 4 N causes a certain copper wire to extend by 1.0 mm. Find the load that will cause a 3.2 mm extension on the same wire. (Assume Hooke’s law is obeyed).
Date posted:
October 12, 2018
.
Answers (1)
-
If the springs shown below are similar and the constant of proportionality (k) is 100 Nm-1, determine total extension in each arrangement.
(Solved)
If the springs shown below are similar and the constant of proportionality (k) is 100 Nm-1, determine total extension in each arrangement.
Date posted:
October 12, 2018
.
Answers (1)
-
Applications of the force on a conductor
(Solved)
Applications of the force on a current carrying conductor.
Date posted:
October 12, 2018
.
Answers (1)
-
State the factors affecting the magnitude of the force on a current carrying conductor
(Solved)
State the factors affecting the magnitude of the force on a current carrying conductor
Date posted:
October 12, 2018
.
Answers (1)