User Forum

Three glass prisms A, B and C of the same refractive index are placed in contact with each other as shown in the figure with no air gap between the prisms.
A ray of light OP passes through the prism assembly and emerges as QR. The condition of minimum deviation is satisfied in the prisms


AA and C only
BB and C only
CA and B only
DA, B and C

Which of the following statements are incorrect?
(i) About 90% of the ozone in our atmosphere is contained in stratosphere.
(ii) The warmest parts of our atmosphere are located in mesosphere.
(iii) Commercial passenger aircrafts usually fly in lower troposphere.
(iv) Satellites orbit around the Earth in thermosphere.

A(iii) and (iv) only
B(ii) and (iii) only
C(i) and (iii) only
D(i) and (iv) only

When Cu is exposed to moist air for a long time, which of the following is formed?

ACu(OH)₂
BCuCO₃
CBoth (A) and (B)
DCu₂O

Different types of changes are listed as :
P - Physical, reversible
Q - Physical, irreversible
R - Chemical, irreversible
S - Both physical and chemical
Some common changes around us are
(i) Decomposition of old leaves
(ii) Burning of a candle
(iii) Shredding of paper
(iv) Melting of an ice cream
Which of the following represents the correct match for the given changes?

AP - (iii), Q - (ii), R - (i), S - (iv)
BP - (iv), Q - (iii), R - (i), S - (ii)
CP - (iv), Q - (iii), R - (ii), S - (i)
DP - (i), Q - (ii), R - (iii), S - (iv)

Which of these correctly shows the animals in the given figure?

(A)

(B)

(C)

(D)

A rocket is launched from the Earth and then it is returning back as shown in the drawings. In which of the three positions does the gravity acts on the rocket?


A 3 only
B 1 and 2 only
C 2 and 3 only
D 1, 2 and 3

Four light bulbs are concealed from an observer by an opaque wall as shown. Without shifting the positions of the observer and the bulbs, how many bulbs can the observer see from the mirror?


A1
B2
C3
D4

The given graph provides information about noise level in different situations. Which of the following scenarios can create a noise level as indicated on the graph by the letter 'X'?


AA plane taking off
BA few dogs barking
CSome people talking loudly
DMetro train moving on tracks

Read the given statements and select the correct option.
Statement 1 : Animals cannot take nitrogen directly from atmosphere rather they obtain it from plants they eat.
Statement 2 : Plants also cannot take nitrogen directly from atmosphere, rather free living or symbiotic nitrogen fixing bacteria present in soil convert atmospheric nitrogen into soluble nitrogen compounds that can be used by plants.

ABoth statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.
BBoth statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.
CStatement 1 is true but statement 2 is false.
DBoth statements 1 and 2 are false.

A body projected vertically from the surface of the earth, reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force

AIs greatest at the highest position of the body
BIs greatest at the instant just before the body hits the earth
CRemains constant throughout the motion
DNone of these.