User Forum

Manomay conducted an experiment where 4 identical metal balls were allowed to roll down 4 similar curves with surfaces of different texture. The time taken for the ball to come to a complete stop for each of the different surfaces was recorded in the table below.

Which curve has the roughest surface?

A P
B Q
C R
D S

Arrange these as first, second and third class levers?

AA, B, C
BB, A, C
CC, B, A
DC, A, B

The young plant shown here was grown from a seed that most likely came from which of the following plants?

(A)

(B)

(C)

An equilibrium state of a body is considered if all the forces acting on it

A are in the same direction
B are equal in magnitude
C have zero resultant
D can be arranged in pairs.

Which pair shows correct match of organism with its breathing organs?

ADolphin-Blow holes
BSnake-Moist skin
CEarthworm-Spiracles
DWhale-Gills

Which of the following statements is false regarding physical and chemical properties?

A The composition of matter need not be changed for observing a physical change.
B During a chemical reaction, molecules undergo a change and their concentration keeps decreasing along with time.
C Chemical property is the ability of matter to undergo some chemical change because of its composition.
D During a chemical reaction, same molecules are present throughout the change.

Sakshi performs a chemical reaction in the laboratory. The change in the position of the molecules is represented in the given figure.

Which of the following chemical reactions was performed by Sakshi?

ACaO (aq) + CO₂ (g)--->CaCO₃ (aq)
B2H₂ (g) + O₂(g)--->2H₂O (l)
CNa (s) + O₂ (g) ---> Na₂O (s)
DH₂ (g) + Cl₂ (g)---> 2HCl (g)