Use a ruler to draw ray diagrams to locate the images of the...

Use a ruler to draw ray diagrams to locate the images of the following objects: (a) an object that is 30 cm from a convex lens of +10-cm focal length, (b) an object that is 14 cm from the same lens, and (c) an object that is 5 cm from the same lens. (Choose a scale so that your drawing fills a significant portion of the width of a paper.) Measure the image locations on your drawings and indicate if they are real or virtual, upright or inverted.

Transcript

00:01 Hello everyone we are going to understand this question here in the part it is given object distance object distance u is equal to that it is represented by u1 which is given 30 centimeter and focal length of converging lens focal length of converging lens convercing lens f is equal to 10 cm.

00:53 Let image be at v.

00:56 Let image v at v.

01:02 Now for converging lens, we know that 1 upon v plus 1 upon u is equal to 1 upon f.

01:16 Now, substituting the values.

01:19 Now substituting the values so here we can write sorry here formula is 1 upon v minus 1 upon u is equal to 1 upon now substituting the value so here we can write 1 upon v is equal to 1 upon f plus 1 upon u again we can write 1 upon v is equal to value of f and that is 10 so 1 upon 10 plus object is as 30 so here will be minus 30 so after calculation we will get b is equal to sorry 1 upon b is equal to lcum will be 30 3 minus 1 that will be 2 upon 30 so b is equal to 15 cm means if this is the length object here this is the focal length object is at 30 so one ray and after after reflection they will be like go like this and here this is the this is the image this is object and this is object and this is image.

03:06 Hence we can say that image will be real and inverted.

03:15 Image will be real and inverted.

03:28 That was the explanation to this question.

03:31 Now we will solve it for b part.

03:36 So here in the part b there is given object distance from the lens.

03:44 Let it is represented by u2.

03:46 Which is given 14 cm and focal length is already given f is equal to 10 centimeter.

03:59 Now again we will apply lens formula 1 upon b minus 1 upon u is equal to 1 upon f so we can write 1 upon v is equal to 1 upon f plus 1 upon u but here object is on left side so you will be minus now substituting value in this so we can write 1 upon v is equal to value of f that is 10 minus 1 upon value of u that is 14 so we will take lcm here lcm will be 70 so 7 minus 5 so it will be 2 upon 70 so after calculation we will get v is equal to 35 centimeters if we will draw the diagram then this is the focal length, primary focal and secondary focal.

05:07 And object is at 14...

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