The near point of an eye is 48.5 cm. A corrective lens is to be used to allow this eye to focus clearly on objects at the distan
1 answer:
Answer:
The focal length of the lens should be -51.5 cm (a concave lens).
Explanation:
The purpose of the lens is to make objects at 48.5 cm appear at the healthy near point. The healthy near point is 25.0 cm.
We use the lens formula
where <em>f</em> = focal length, <em>u</em> = object distance and <em>v</em> = image distance.
In this case, <em>u</em> = 48.5 cm and <em>v</em> = -25.0 cm.
<em>v</em> is negative because the image is virtual an not real. (Here, we are using the real-is-positive sign convention)
The negative sign indicates the lens is concave.
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Answer:
Explanation:
For this case we have the following info given:
Number of Na+ ions
Each ion have a charge of +e and the crage of the electron is
The time is given if we convert this into seconds we got:
Now we can use the following formula given from the current passing thourhg a meter of nerve axon given by:
Where N represent the number of ions, e the charge of the electron and Q the total charge
If we replace on this case we have this:
And from the general definition of current we know that:
And since we know the total charge Q and the time we can replace:
The current during the inflow charge in the meter axon for this case is
Answer:
103.1 V
Explanation:
We are given that
Initial circumference=C=168 cm
Magnetic field,B=0.9 T
We have to find the magnitude of the emf induced in the loop after exactly time 8 s has passed since the circumference of the loop started to decrease.
Magnetic flux=
Circumference,C=
cm
When t=0
E=
t=8 s
B=0.9