Question Discussion & Solution

The correct answer is On 6th April 1919.

• The non-violent protest day of Rowlatt Act was celebrated on 6th April 1919. 

Key Points

• ​Rowlatt Act (1919):
  • In 1919 a Sedition Committee headed by justice Rowlatt led to the Rowlatt Act. This act authorised the government to imprison any person without trial and conviction by the Court of Law for 2 years. The law also enabled the government to suspend the right of Habeas Corpus which had been the foundation of civil liberties in Britain.
• Jallianwala Bagh Massacre (13th April 1919 AD):
  • The arrest of Dr Saifuddin Kitchlu and Dr Satyapal on 10th April 1919 AD, under the Rowlatt Act in connection with Satyagraha caused serious unrest in Punjab.
  • A public meeting was held on 13th April 1919 AD in a park called Jallianwala Bagh in Amritsar. As soon as the meeting started, General Reginald Dyer ordered the indiscriminate heavy firing. The crowd of people had no way out to escape. As a result, hundreds of men, women and children were killed and more than 1,200 people wounded.
  • Due to this massacre, R.N. Tagore returned ‘Knighthood’ and Shankaran Nair resigned from the Executive Council of Viceroy.

Concepts:

Physical Properties of Metals and Non-metals

Explanation:

• Iodine is lustrous. This is an exception to the physical properties of non - metals. Iodine is non-metal and non - metals have dull appearance. 
• Sodium is metal. Metals are usually hard so this is also an exception. 
• Graphite conducts electricity. This is an exception as graphite is a form of carbon and it is non - metal. 
• Copper being metal is not an exception as it is metals and metals are good conductors of heat. 

So the correct option is 'Copper is a good conductor of heat.'

The correct answer is option 3 i.e. the Atomic Number

• The periodic table is based on Atomic Number.
• The atomic number is the number of protons found in the nucleus of every atom of that element. 
• The periodic table is managed by the International Union of Pure and Applied Chemistry, or IUPAC.
• In 1869, Dimitri Mendeleev included 63 known elements arranged according to increasing atomic weight. But there were many elements he could not place in the periodic table and with the discovery of new noble elements, there was a need to arrange the elements. Henry Moseley later arranged the elements in the periodic table by their number of protons rather than their atomic weights.
• The modern periodic table orders the elements according to increasing atomic number rather than increasing atomic weight.
• There are 118 elements in a periodic table. There are seven periods and eighteen groups in the modern periodic table.
• On moving from left to right in a period, the size of atoms(atomic size) decreases.
• On moving from left to right in a period, the metallic character of elements decreases, whereas the non-metallic character increases.
• While going down in a group of the periodic table, the size of atoms increases (or atomic size increases).
• While going down in a group of the periodic table, the metallic character of elements increases.
• Electronegativity and reactivity of non-metals increase along the period and decrease down the group.

Concept:

The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country".

The GROUP BY statement is often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns.

GROUP BY Syntax

SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
ORDER BY column_name(s);

The ORDER BY keyword is used to sort the result-set in ascending or descending order.

The ORDER BY keyword sorts the records in ascending order by default. To sort the records in descending order, use the DESC keyword.

ORDER BY Syntax

SELECT column1, column2, ...
FROM table_name
ORDER BY column1, column2, ... ASC|DESC;

1^st letter: increase by - 8, - 4, - 2, - 1

P - 8→ H - 4→ D - 2 → B - 1 → A

2^nd letter: second letter increase by + 2

K + 2→ M +2 → O + 2 → Q + 2 → S

3^rd letter: Decrease by - 1

R - 1→ Q – 1 → P - 1 → O – 1 → N