Evan's Space

Wonders of Physics


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Different Lens Ray Diagram questions

Drawing ray diagrams for converging lens come in many forms. But the basic concepts needed are the 3 rays (which have rules to follow) to locate the image. The following ray diagrams for the 4 scenarios must be learned well, together with the respective image characteristics and applications.

IMG_1375

 

With the basic concepts learned, when questions are asked in different ways, you should be able to draw the ray diagrams. Refer to some different ray diagram questions below and their video tutorials.

A

 

b.jpg

 

C

 

D

E

F

G

H

I

J

Lens J from evantoh on Vimeo.

Click the followings for other lens ray diagram questions. https://evantoh23.wordpress.com/2010/11/09/20101109converging-lens-important-concepts/

https://evantoh23.wordpress.com/2015/08/27/olevel-sp-p1-focal-length-of-lens-using-distant-object/


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Magnetic field around a magnet and an electromagnet

Electromagnet is like a ‘temporary magnet’. When a current flows through the solenoid, it will be magnetised. When the current is switched off, the eletromagnet loses its magnetism.

To make the electromagnet stronger,

1) Increase the number of turns in the solenoid.
2) Increase the size of the current.
3) Insert a soft iron core in the solenoid.
– iron is a soft magnetic material
– it can be magnetised easily
– it can be demagnetised easily