21) Actinides are the elements with atomic numbers from
A. 97 to 104
B. 101 to 115
C. 89 to 103
D. 36 from 43
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Answer Option C
22) The filament of an electric bulb is made of
A. tungsten
B. nichrome
C. graphite
D. iron
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Answer Option A
23) In fireworks, the green flame is produced because of
A. sodium
B. barium
C. mercury
D. potassium
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Answer Option B
24) Marsh gas is
A. nitrogen
B. ethane
C. methane
D. hydrogen
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Answer Option C
25) Air is a/an
A. compound
B. element
C. electrolyte
D. mixture
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Answer Option D
 Questions in Competitive Examinations){kind=link}