When a radioactive substance emits an α-particle, its position in the periodic table is lowered by which of the following?

Which of the following statement(s) is/are false regarding the modern periodic table? i. In the modern periodic table, the elements are arranged in decreasing order of their atomic numbers. ii. In the modern periodic table, the elements are arranged in increasing order of their atomic masses. iii. In the modern periodic table, isotopes are placed in adjacent groups. iv. In the modern periodic table, the elements are arranged in increasing order of their atomic numbers.

A

Only (i)

B

Only (iv)

C

(i), (ii) and (iv)

D

(i), (ii) and (iii)

Which of the following statements is/are false regarding modern periodic table?
1. Elements in the modern periodic table are arranged in decreasing order of their atomic numbers.
2. Elements in the modern periodic table are arranged in increasing order of their atomic masses.
3. In the modern periodic table, isotopes are placed in adjacent groups.
4. Elements in modern periodic table are arranged in increasing order of their atomic numbers.

A

only 1

B

only 4

C

1, 2 and 4

D

1, 2 and 3

Which of the following statements are true?
1. All radioactive elements decay exponentially with time.
2. Half-life time of radioactive elements is the time required for one-half of the radioactive atoms to disintegrate.
3. Age of the earth can be determined by radioactive dating.
4. Half-life time of a radioactive element is fifty percent of its average life period.
Select the correct answer:

A

1 and 3

B

1, 3 and 4

C

1, 2 and 3

D

2 and 3

Nuclear wastes is waste that contains radioactive material. Radioactive material is normally a by product of nuclear power generation. Radioactive waste is regulated by government agencies in order to protect human health and the environment. Radioactivity naturally decays over time, so radioactive waste has to be isolated and confined in appropriate disposal facilities for a sufficient period until it no longer poses a threat. Which of the following statements can be inferred from the paragraph?

A

Radioactive material is very expensive.

B

Since radioactive material decays over time, it is not hazardous.

C

Radioactive material is extremely hazardous to humans.

D

Disposal of radioactive material, is extremely difficult.

Which of the following statements are true regarding the trends in the modern periodic table? i. Atomic radius increases on going right in the periodic table. ii. Ionization energy increases as we go right in the periodic table. iii. Electron affinity increases as we go down in the group.

A

Statement (i) is true only

B

Statement (ii) is true only

C

Statement (iii) is true only

D

None

The half life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half life period of a radioactive substance is one month, then

A

$${\frac{3}{4}^{{\text{th}}}}$$ of it will disintegrate in two months

B

It will completely disintegrate in two months

C

It will completely disintegrate in four months

D

$${\frac{l}{8}^{{\text{th}}}}$$ of it will remain intact at the end of four months

The half-life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half-life period of a radioactive substance is one month, then?

A

it will completely disintegrate in two months

B

l/8th of it will remain intact at the end of four months

C

3/4th of it will disintegrate in two months

D

it will completely disintegrate in four months

There are seven persons Amit, Roshan, Ravi, Priya, Amrita, Arpita and Mitul. They participated in a competition where they got different positions. Amit scored the first position while Mitul scored the last position. Priya scored fourth position from the last. Ravi scored one position higher than Priya while Amrita scored one position lower than Priya. Roshan scored higher position than five of them. Who scored the second lowest position?

A

Arpita

B

Amrita

C

Ravi

D

Roshan

There are six people Kirti, Kavita, Komal, Khushi, Koel and Kritika, who got different positions in a competition. Kavita got second position while Khushi got third position from the last. Komal’s position was immediately after Kavita and immediately before Khushi. Koel does not get either the first position or the last position. Kirti also does not get the last position. Who got the last position?

A

Khushi

B

Koel

C

Kirti

D

Kritika

Which two of the following are true regarding the distance-vector and link-state routing protocols?
1. Link state sends its complete routing table out all active interfaces on periodic time intervals.
2. Distance vector sends its complete routing table out all active interfaces on periodic time intervals.
3. Link state sends updates containing the state of its own links to all routers in the internetwork.
4. Distance vector sends updates containing the state of its own links to all routers in the internetwork.

A

1 only

B

3 only

C

2 and 3 only

D

None of the above

When a radioactive substance emits an α-particle, its position in the periodic table is lowered by which of the following?

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