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Focal Length of Lenses

PHY 201 & 231

Lab PDF 1
Lab PDF 2

Based on Loyd #41. Students use a precision optics bench and several lenses alone and in combination to form real and virtual images. Converging lenses have a positive focal length and form both real and virtual images, while diverging lenses have a negative focal length and form only virtual images. Students form a real image of a distant object with a converging lens and determine the focal length of that lens. The students will also measure the focal length of a diverging lens by using it in combination with a converging lens to form a real image.


Name Location Quantity
Light Sources JE-105A-D29 1 per table
Holder, Lens JE-105A-D34,D12 2 per table
Object Screens JE-105A-D23 1 per table
Clamp, Optics Bench JE-105A-D30, D31 5 per table
Optics Bench End Supports JE-105A-D31 2 per table
Rods, Clip JE-105A-D24 1 per table
Image Screens JE-105A-D26, D35 1 per table
Optics Bench Rod JE-105A (Next to File Cabinet) 1 per table
Ruler, Transparent, Flexible JE-105A-D90 2 per table
Tape, Masking JE-105A-D63 1 per table
Teaching Lenses, Black (Focal Length: -15cm) JE-105A-D32 1 per room
Teaching Lenses, Green (Focal Length: 12.5cm) JE-105A-D32 1 per room
Teaching Lenses, Red (Focal Length: 24.5cm) JE-105A-D32 1 per room
Protractor JE-105A-D90 2 per table


Object mesh mounts to zero on scale, light bulb mounts off scale beyond zero mark.

1.) Put out ONLY red, green and black lenses.
2.) Leave one extra light fixture in the back of the room.

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Item modified on 2015-07-15 15:28:56 by damicoa6.