Any lump of osmium is. Iridium and gold are also very close.
Answer:
10 GHz
Explanation:
Applying,
v = λf.................... Equation 1
Where v = speed of microwave, λ = wavelength, f = frequency.
make f the subject of the equation
f = v/λ................ Equation 2
Note: Microwave is an electromagnetic wave, and all electromagnetic wave have the same speed, which is 3×10⁸ m/s
From the question,
Given: λ = 3 cm = 0.03 m
Constant; v = 3×10⁸ m/s
Substitute these values into equation 2
f = 3×10⁸/(0.03)
f = 10¹⁰ Hz
f = (10¹⁰/10⁹) GHz
f = 10 GHz
Answer:
#see solution for details
Explanation:
-Uncertainty refers to an estimate of the amount by which a result may differ from this value,
-Precision refers to how closely repeated measurements agree with each other.
-Accuracy refers to how closely a measured value agrees with the correct value.
-The number of significant figures is the number of digits believed to be correct by the person doing the measuring. Therefore, choosing the correct number of significant figures reduces the deviation from the point of accuracy/uncertainty or precision and thereby reducing margin of error in the ensuing calculations.
Because the number of valence electrons of an element determines the properties and in particular the reactivity of that element.
In fact, elements of the first group (i.e. only one valence electron) have high reactivity, because they can easily give away their valence electron to atoms of other elements forming bonds. On the contrary, elements of the 8th group (noble gases) have their outermost shell completely filled with electrons, so they do not have valence electrons, and they have little or no reactivity at all.
'C' is a simple explanation of astigmatism.