the object distance of both lenses are positive.
Answer:
B. +m
Explanation:
The magnification of an image is defined as the ratio between the size of the image and of the object:
![m = \frac{y'}{y}](https://tex.z-dn.net/?f=m%20%3D%20%5Cfrac%7By%27%7D%7By%7D)
where we have
y' = size of the image
y = size of the object
There are two possible situations:
- When m is positive, y' has same sign as y: this means that the image image is upright
- When m is negative, y' has opposite sign to y: this means that the image is upside down
Therefore, the correct option representing an upright image is
B. +m
Answer:
248
Explanation:
L = Inductance of the slinky = 130 μH = 130 x 10⁻⁶ H
= length of the slinky = 3 m
N = number of turns in the slinky
r = radius of slinky = 4 cm = 0.04 m
Area of slinky is given as
A = πr²
A = (3.14) (0.04)²
A = 0.005024 m²
Inductance is given as
![L = \frac{\mu _{o}N^{2}A}{l}](https://tex.z-dn.net/?f=L%20%3D%20%5Cfrac%7B%5Cmu%20_%7Bo%7DN%5E%7B2%7DA%7D%7Bl%7D)
![130\times 10^{-6} = \frac{(12.56\times 10^{-7})N^{2}(0.005024)}{3}](https://tex.z-dn.net/?f=130%5Ctimes%2010%5E%7B-6%7D%20%3D%20%5Cfrac%7B%2812.56%5Ctimes%2010%5E%7B-7%7D%29N%5E%7B2%7D%280.005024%29%7D%7B3%7D)
N = 248
Energy is calculated as power*time, so give the wattage of 1200 W (equivalent to 1200 Joules/second) and time of 30 seconds, multiplying these gives 36000 J or 36 kJ of electrical energy.
If electrical charge or current is needed: Power = voltage * current, so given the power of 1200 watts and voltage of 120 V, current is 1200 W / 120 V = 10 Amperes. Charge is calculated by multiplying 10 A*30 s = 300 C.
Because you have to study about electricity, first of all, and also need to study about polarity