Answer:
0.4
Explanation:
A concave lens is a diverging lens, so it will always have a negative focal length. Image distance is always negative for a concave lens because it forms virtual images.
From the lens formula;
1/f = 1/u+ 1/v
- 1/2 = 1/3 - 1/v
1/v = 1/3 + 1/2
v= 6/5
v= 1.2 cm
Magnification = image distance/object distance
Magnification = 1.2cm/3cm
Magnification = 0.4
A thermostat is a switch that operates itself when the temperature
goes above or below a temperature that the user can set.
-- Before you go to bed, you set the thermostat for 65° .
If the temperature in the house goes below 65° during the night,
the thermostat turns on the furnace, and keeps it running until
the house warms up to 65°. Then it shuts the furnace off.
-- After breakfast, you set the thermostat for 75°.
If the temperature in the house goes above 75°, during the day,
the thermostat turns on the air conditioner, and keeps it running until
the house cools down to 75°. Then it shuts the air conditioner off.
-- On Sunday morning, you put the slow cooker on the kitchen counter,
and you throw in a big roast, a sliced onion, some baby carrots, some
sliced potatoes, some vegetable stock, salt, pepper, garlic, chili powder,
and tomato paste. Then you put the cover on, turn the power on, and
set the slow cooker to "LOW". The heater in the slow cooker turns on.
Whenever the temperature in the crock gets higher than 160°, the
thermostat in the slow cooker turns off the heater, and keeps it off
until the crock cools down to 160°. Then the thermostat turns the
heater on again.
By dinner time, you have a hot, juicy, scrumptious pot roast, ready
to eat. It's not too hot, not too cold, not too tough, not dried out, and
it melts in your mouth.
You're still thinking about it when you go to bed, and your mom gives you
a slice to take to school for your lunch on Monday.
<span>This is known as a "solar eclipse." The Moon partially or completely covers the Sun, leading to a rapidly moving shadow across the sunlit face of the Earth.</span>
Answer:
1.492*10^14 electrons
Explanation:
Since we know the mass of each balloon and the acceleration, let’s use the following equation to determine the total force of attraction for each balloon.
F = m * a = 0.012 * 1.9 = 0.0228 N
Gravitational forces are negligible
Charge force = 9 * 10^9 * q * q ÷ 225
= 9 * 10^9 * q^2 ÷ 225 = 0.0228
q^2 = 5.13 ÷ 9 * 10^9
q = 2.387 *10^-5
This is approximately 2.387 *10^-5 coulomb of charge. The charge of one electron is 1.6 * 10^-19 C
To determine the number of electrons, divide the charge by this number.
N =2.387 *10^-5 ÷ 1.6 * 10^-19 = 1.492*10^14 electrons
