Answer:
The focal length of the lens and the height of the image are -6.86 cm and -0.638 cm.
Explanation:
Given that,
Distance of the object u = -16.0 cm
Distance of the image v = -12.0 cm
Height of the object = 8.50 mm = 0.85 cm
(a). We need to calculate the focal length
Using lens's formula
Where, f = focal length
u = distance of the object
v = distance of the image
Put the value into the formula
The lens is diverging.
(b). Using formula of magnification
Put the value in to the formula
The image is inverted.
Hence, The focal length of the lens and the height of the image are -6.86 cm and -0.638 cm.
Answer:
2.6 g/cubic centimeter
Explanation:
Given :
Weight of the quartz = 13 gram
Original level of water = 30mL
Level of water after quartz was is placed inside the cylinder = 35 mL
Therefore rise in water = 35 - 30 = 5 mL
We known that 1 mL = 1 cubic centimeter
And density = mass / volume
Therefore, density of the quartz is = 13/5
= 2.6 g/ cubic centimeter
Answer;
D. The group number is equal to the number of valence electrons.
Explanation;
-The valence electrons are the electrons in the outer shell of an atom. The valence electrons are the ones involved in forming bonds to adjacent atoms. Therefore, the number of valence electrons is important for determining the number of bonds an atom will form, the number of unpaired electrons, and an atom’s formal charge.
-For neutral atoms, the number of valence electrons is equal to the atom’s main group number.
Number of valence electrons = main group number (neutral atoms)
-The main group number for an element can be found from its column on the periodic table. For example, carbon is in group 4 and has 4 valence electrons. Oxygen is in group 6 and has 6 valence electrons.
Friction is a force that acts in a direction opposite to motion. If there were not force of friction, a baseball player would never stop and would be continuously moving in the direction of motion. Balanced forces do not cause a nonmoving object to start moving.
Mercury does not wet glass because of the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass.