Answer:
Let the volume of the block of wood be
V
c
m
3
and its density be
d
w
g
c
m
−
3
So the weight of the block
=
V
d
w
g
dyne, where g is the acceleration due to gravity
=
980
c
m
s
−
2
The block floats in liquid of density
0.8
g
c
m
−
3
with
1
4
t
h
of its volume submerged.So the upward buoyant force acting on the block is the weight of displaced liquid
=
1
4
V
×
0.8
×
g
dyne.
Hence by cindition of floatation
V
×
d
w
×
g
=
1
4
×
V
×
0.8
×
g
⇒
d
w
=
0.2
g
c
m
-3
,
Now let the density of oil be
d
o
g
c
m
-3
The block floats in oil with 60% of its volume submerged.So the buoyant force balancing the weight of the block is the weight of displaced oil =
60
%
×
V
×
d
o
×
g
dyne
Now applying the condition of floatation we get
60
%
×
V
×
d
o
×
g
=
V
×
d
w
×
g
⇒
60
100
×
V
×
d
o
×
g
=
V
×
0.2
×
g
⇒
d
o
=
0.2
×
10
6
=
1
3
=
0.33
g
c
m
−
3
Explanation:
Answer:
Alkali metals
Explanation:
The lowest number of valence electrons is found in the alkali metals (group 1), which have only one valence electron per atom.
Among BF₃, NF₃, OH⁻ and ALCl₃ both NF₃ and OH⁻ acts as a lewis base.
Explaination:
According to lewis theory of acid and base, base is a specie which has either lone pair of electrons or is negatively charged. So, in the given compounds Nitrogen trifluoride contain lone pair of electron on nitrogen and Hydroxide contains a negative charge on oxygen. And botha are capable to donate these electrons to a lewis acid (electrophiles).
I believe the answer is red, they have the longest wavelength, and energy.
Hope this helps
The answer is B. The less mass then the less the gravity pulls on it