Charge = number of proton - number of electron = 18-22 = -4
SO, OPTION A IS YOUR ANSWER........
Answer:
Explanation:
The theory of natural selection was explored by 19th-century naturalist Charles Darwin. Natural selection explains how genetic traits of a species may change over time. This may lead to speciation, the formation of a distinct new species.
During photosynthesis, what gas do plants release - oxygen
Answer:
work done = 750 J
Explanation:
Given data:
Force on object = 50 N
Distance covered = 15 m
Work done = ?
Solution:
W = F. d
W = work done
F = force
d = distance
Now we will put the values in formula.
W = 50 N × 15 m
W = 750 N. m = 750 J
Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶


Density of iron bar

= 7870 kg/m³ (3 s.f.)
7.

Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³

Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume

(3 s.f.)