1
AP EAPCET 2021 - 20th August Evening Shift
MCQ (Single Correct Answer)
+1
-0

The main constituent of enamel on the surface of teeth is

A
$$\left[3 \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2 \cdot \mathrm{CaF}_2\right]$$
B
$$\left[\mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2 \cdot \mathrm{H}_2 \mathrm{O}\right]$$
C
$$\left[3 \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2 \cdot \mathrm{Ca}(\mathrm{OH})_2\right]$$
D
$$\mathrm{CaF}_2$$
2
AP EAPCET 2021 - 20th August Evening Shift
MCQ (Single Correct Answer)
+1
-0

$$\mathrm{H}_3 \mathrm{BO}_3$$ or $$\mathrm{B}(\mathrm{OH})_3$$ is considered as an acid because its molecule

A
combines with proton from water molecule
B
accepts $$\mathrm{OH}^{-}$$ from water, releasing a proton
C
contains replaceable $$\mathrm{H}^{+}$$ ion
D
can donate proton easily
3
AP EAPCET 2021 - 20th August Evening Shift
MCQ (Single Correct Answer)
+1
-0

The element with maximum bond energy is

A
C
B
Pb
C
Ge
D
Si
4
AP EAPCET 2021 - 20th August Evening Shift
MCQ (Single Correct Answer)
+1
-0

Identify the coldest region among the following layers of atmosphere.

A
Troposphere
B
Mesosphere
C
Stratosphere
D
Thermosphere