1
NEET 2019
MCQ (Single Correct Answer)
+4
-1
Change Language
The work done to raise a mass m from the surface of the earth to a height h, which is equal to the radius of the earth, is :
A
mgR
B
2mgR
C
$${1 \over 2}$$mgR
D
$${3 \over 2}$$mgR
2
NEET 2019
MCQ (Single Correct Answer)
+4
-1
Change Language
For a p-type semiconductor, which of the following statements is true?
A
Holes are the majority carriers and trivalent atoms are the dopants.
B
Holes are the majority carriers and pentavalent atoms are the dopants.
C
Electrons are the majority carriers and pentavalent atoms are the dopants
D
Electrons are the majority carriers and trivalent atoms are the dopants.
3
NEET 2019
MCQ (Single Correct Answer)
+4
-1
Change Language
$$\alpha $$-particale consists of :
A
2 electrons, 2 protons and 2 neutrons
B
2 electrons and 4 protons only
C
2 protons only
D
2 protons and 2 neutrons only
4
NEET 2019
MCQ (Single Correct Answer)
+4
-1
Change Language
Pick the wrong answer in the context with rainbow.
A
An observer can see a rainbow when his front is towards the sun.
B
Rainbow is a combined effect of dispersion refraction and reflection of sunlight.
C
When the light rays undergo two internal reflections in a water drop, a secondary rainbow is formed.
D
The order of colours is reversed in the secondary rainbow.