# what are light gates??????Watch

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#1
I'm doing physics as level, and I am revising and LIGHT GATES has come up... What is it? How do they work? What do they measure??? I am clueless. Please help! Many thanks.
1
7 years ago
#2
Detectors. They detect when something goes through them and how long it takes to cross.
The light gate has a beam going from one LED/IR light source onto a detector. As something goes through it, the beam is "Cut".
The light gate measure how long the beam has been cut for. That gives you a measure for time.
Some light gates will allow you to plug in the length of the crossing object, and then it'd automatically calculate:
Length of object/time = How fast it was travelling.
15
#3
(Original post by tamimi)
Detectors. They detect when something goes through them and how long it takes to cross.
The light gate has a beam going from one LED/IR light source onto a detector. As something goes through it, the beam is "Cut".
The light gate measure how long the beam has been cut for. That gives you a measure for time.
Some light gates will allow you to plug in the length of the crossing object, and then it'd automatically calculate:
Length of object/time = How fast it was travelling.
I can't thank you enough! +ve rep for you.
2
7 years ago
#4
(Original post by sharmine)
I can't thank you enough! +ve rep for you.
Merci Buckets.
2
4 years ago
#5
my name is jeff
1
1 year ago
#6
what unit do they measure in?
1
1 year ago
#7
(Original post by 2221)
what unit do they measure in?
metres per second. The unit of speed.
1
1 year ago
#8
(Original post by 2221)
what unit do they measure in?
(Original post by Iluv2edgedsword)
metres per second. The unit of speed.
Hi both This is an old thread - please try and create new ones if you want to ask a question.

Going to close this now.
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