Answer:
The image distance is 30 cm
image height = - 5 cm
Explanation:
The formula for calculating the image distance is expressed as
1/f = 1/u + 1/v
where
f is the focal length
u is the object distance
v is the image distance
From the information given,
u = 30
f = 15
By substituting these values into the formula,
1/15 = 1/30 + 1/v
1/v = 1/15 - 1/30 = (2 - 1)/30 = 1/30
Taking the reciprocal of both sides,
v = 30
The image distance is 30 cm
magnification = image height/object height = - v/u
Given that object height = 5 cm, then
image height/5 = - 30/30 = - 1
image height = - 5 * 1
image height = - 5 cm
Answer: current is 8.0 A
Explanation: R= U/I I = U/R = 120 V/15 Ω= 8.0 A
Resistors and reactors, for use over 600 volts, shall not be installed in close enough proximity to combustible materials to constitute a fire hazard and shall have a clearance of not less than<u> 300 mm </u>from combustible materials.
Explanation:
- The hazards associated with high power industrial resistors are primarily due to their open construction, which is necessary for cooling.
- The exposed conductors which make up the resistors can be not only a shock hazard but also a thermal burn hazard.
- When a resistor fails, it either goes open or the resistance increases. When the resistance increases, it can burn the board, or burn itself up.
- Avoid touching non-flammable resistors in operation; the surface temperature ranges from approximately 350 °C to 400°C when utilized at the full rated value. Maintaining a surface temperature of 200°C or less will extend resistors service life.
- Do not apply power to a circuit while measuring resistance. When you are finished using an ohmmeter, switch it to the OFF position if one is provided and remove the leads from the meter.
- Always adjust the ohmmeter for 0 (or in shunt ohmmeter) after you change ranges before making the resistance measurement.
Answer: 12.0 m/s^2
Explanation:
Let
be the angular acceleration of the end of the rod
Taking torque about the link, we have:

Torque is also given in terms of moment of inertia of the rod and its angular acceleration i.e.

From equations (i) and (ii) we have:

The acceleration of the end of the rod farthest from the link is given by:

Answer: Choice B
There are triple bonds between the carbon (C) and oxygen (O) atoms. Then there are 2 dots on either side
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Explanation:
When it comes to interaction and chemistry, all that matters is the valence shell or valence electrons. This is the outermost shell. This is because various elements do not interact with the inner electrons (they're locked in place so to speak and don't move to other elements).
Carbon has 6 protons, which is what uniquely makes up this element. This means there are 6 electrons. The inner shell has 2 electrons and the valence shell has 4 electrons. Two electrons are shown as the two blue dots on the left side of the C. The other two electrons form two of the lines, or the bonds, between the C and O.
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Oxygen has 8 protons and 8 electrons. It has 2 electrons in the inner shell and 6 electrons in the valence shell. Two of those electrons are the red dots on the right side of the O. The other 4 electrons are shared to form the bonds with the carbon atom.
This is where things get a bit tricky. I've shown a diagram below indicating that one of the oxygen electrons (red dot) is passed to the carbon, as this carbon atom is pulling on the oxygen electron. But the oxygen atom is pulling on it as well, which forms one of the triple bonds.
So this is why diagram B is the final answer. This is something you can logically determine (remembering the rules of how each electron shell is formed), or it's something you'll need to memorize. In the real world, it's easy to forget a lot of info like this, so that's why having it handy as a lookup reference is preferable.