When cathode rays strike anode of a certain element in the discharge tube, then the rays emmited are;

1. alpha particles
2. x-rays
3. ?-rays
4. beta particle
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Answer: B
Explanation:
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As the atomic number of element increases, the wavelength of emitted x-rays;

1. increases
2. decreases
3. remains constant
4. may increase or decrease
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Answer: B
Explanation:
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As the atomic number of element increases, the frequency of emitted x-rays;

1. increases
2. decreases
3. remains constant
4. may increase or decrease
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Answer: A
Explanation:
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According to Moseley's law the atomic number of element emmiting x-rays varies;

1. directly with frquency of x-rays
2. inversely with frquency of x-rays
3. directly with square of frquency of x-rays
4. directly with square root of frquency of x-rays
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Answer: D
Explanation:
• Moseley's law expression
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Mass number is equal to the number of -------- in the nucleus of an atom;

1. protons
2. nucleons
3. neutrons
4. protons and electrons
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Answer: B
Explanation:
• Nucleons are protons and neutrons present in the nucleus
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Atomic number and mass number of phosphorous are 15 and 31 respectively, the number of neutrons in the nucleus is;

1. 15
2. 31
3. 16
4. 46
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Answer: C
Explanation:
• n = A - Z
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There is no neutron in the nucleus of the element;

1. Hydrogen
2. helium
3. Iron
4. none of these
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Answer: A
Explanation:
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Which one of the followings contains no neutron in its nucleus;

1. Deutrium
2. helium
3. protium
4. none of these
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Answer: C
Explanation:
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Neil Bohr was a;

1. Danish physicist
2. German chemist
3. English physicist
4. Greek scientist
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Answer: A
Explanation:
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Bohr's atomic theory was based on:

1. Classical mechanics
2. Quantum theory
3. Simple old laws of physics
4. none of these
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Answer: B
Explanation:
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