<span>In a
real machine, the work output is always less than the work input is true. The answer
is letter A. it follows the law of entropy where no energy can be converted completely
into work. Under this law, Carnot’s theorem states that Carnot’s engine can
perform 100% of work. However, no such engine has ever succeeded the conversion
of work into 100%. The greatest efficiency so far is at 80%. Because there will always be factors that
could affect the conversion of work. </span>
Answer:
The line charge density is 
Explanation:
Given that,
Diameter = 2.54 cm
Distance = 19.6 m
Potential difference = 115 kV
We need to calculate the line charge density
Using formula of potential difference



Where, r = radius
V = potential difference
Put the value into the formula


Hence, The line charge density is 
The time for half the atoms in a radioactive substance to disintegrate
https://www.vocabulary.com/dictionary/half-life
Answer: • using beaker tongs to handle the hot beaker.
• checking the beaker for chips prior to heating on the hot plate.
• Turning off the hot plate after use
Explanation:
The options that will ensure laboratory safety during the experiment will be:
• using beaker tongs to handle the hot beaker.
• checking the beaker for chips prior to heating on the hot plate.
• Turning off the hot plate after use.
We should note that the beaker tongs are simply used in the holding of the beakers that have hot liquids in them. Also, it s vital for the hot plate to be turned off after its use so as to prevent accident.