The focal length of the mirror is 15 cm
From the question given above, the following data were obtained:
Object distance (u) = 30 cm
Image distance (v) = 30 cm
<h3>Focal length (f) =? </h3>
The focal length of the mirror can be obtained as follow:

<h3>Invert </h3><h3>f = 15 cm</h3>
Therefore, the focal length of the mirror is 15 cm
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Answer:
1.6605 × 10⁻²³ g / atom , 9.99 amu
Explanation:
Atoms present in 1 mole = 6.022 × 10²³ atoms
Given that
Moles of common Eastern mole = 8.3 moles
So,
Atoms in 8.3 moles are:
8.3 moles = 6.022 × 10²³ × 8.3 atoms
Also,
Average mass = Mass of the sample / Number of atoms
Mass of sample = 83 g
Average mass = 83 g / 6.022 × 10²³ × 8.3 atoms = 1.6605 × 10⁻²³ g / atom
In amu :
1 amu = 1.66 × 10⁻²⁴ g / atom
So,
Average mass = 1.6605 × 10⁻²³ / 1.66 × 10⁻²⁴ amu = 9.99 amu
Explanation:
Fe2o3+ 3co ---------. 2fe + 3co2
Explanation:
There are three states of matter:
1) Solid: In this state, the particles lie closer to each other. there is a strong intermolecular force of attraction between the particles.
2) Liquid: In this state, the particles are at a certain distance to each other. There is an intermediate intermolecular force of attraction between the particles.
3) Gas: In this state, the particles are farther from each other. There is weaker intermolecular force of attraction between the particles.
As the number of carbon atoms in a molecule increases, the number of particles increases and the particles will come closer to each other. Hence, the state of matter will shift towards the solid state.
Viscosity is defined as the tendency to resist the particles to flow. As, the number of carbon atoms increases, the Vander-Walls forces increases, the particles are closer to each other and Hence, the viscosity will increase.
Answer: Option (c) is the correct answer.
Explanation:
As we know that density the amount of mass present in per unit volume.
Mathematically, Density = 
So, it means that density is inversely proportional to volume. Hence, when there will be decrease in density of a substance then there will be increase in its volume. That is, expansion of substance will take place.
Also, boiling point of copper is 2,562 degree celsius but we are heating it up to a temperature of 95 degree celsius. This means that copper will remain in liquid state at this temperature.
Thus, we can conclude that a change which occurs in a sample of copper is that copper sample will expand.