User Forum

A wire is being drawn to make it thinner such that the length of the wire l increases and radius r decreases. Its resistance R will finally be proportional to

A
B
C
D

Three hydrocarbons P, Q and R have carbon which combine with hydrogen in the ratio of 3 : 2 : 1 respectively. Which of the following is incorrect about the reactions shown by P, Q and R?

A P does not undergo addition reactions.
B Both Q and R decolourise bromine water.
C Both Q and R give white precipitate with AgNO₃ solution dissolved in NH₄OH.
D None of these.

Two equilateral prisms are arranged as shown in diagram.

If white light incident on prism X then
Statement 1 : The ray of light which emerges out of the prism Y will be white light.
Statement 2 : The refraction produced by the prism Y is equal and opposite to that produced by prism X.

A Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.
B Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.
C Statement 1 is true but statement 2 is false.
D Statement 1 is false but statement 2 is true.

The given figure shows a diagram of eye. Which of the following correctly lists the names of marked parts of the eye?

A small conducting rod of length l, moves with a uniform velocity v in a uniform magnetic field B as shown in figure.


A The end X of the rod becomes positively charged.
B The end Y of the rod becomes positively charged.
C The entire rod is unerringly charged.
D The rod becomes hot due to joule heating.

Read the given passage and answer the following questions.
Siddhi studied forelimbs of three organisms and described them as follows :
Organism X – Long and short bones, covered with muscles, used for running.
Organism Y – Long and short bones, covered with feathers used for flying.
Organism Z – A layer of a complex chemical with supporting framework which is not made of bones and used for flying.
Select the option that shows correct relationship between these organisms.

A
B
C
D

Humans inherit colour of their eyes from their parents. Brown-eyed couple has three blue-eyed children. Which of the following statements gives correct explanation of this situation?
(i) Each parent has an allele for brown eyes and an allele for blue eyes.
(ii) The allele for blue eyes is recessive.
(iii) The probability that their next child will have blue eyes is 0.75.
(iv) The probability that their next child will have brown eyes is 0.5.

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

Shaheen, a class 10 student studied the speed of the given reaction under different conditions.

In experiment I, she added 1 g of MnO₂ (catalyst) to 75 cm³ of 0.4 mol/L H₂O₂ solution at 30°C In experiment II, she added 1 g of MnO₂ to 100 cm³ of 'X' mol/L H₂O₂ solution at 'T' °(C) She recorded her observations and plotted a graph as shown in the given figure.
The values of X and T in experiment II could be respectively


A 0.30 and 35
B 0.40 and 30
C 0.25 and 30
D 0.30 and 30.

In an experiment, 0.03 mol of a hydrocarbon reacted completely with 30 cm³ of bromine solution of 2 mol/L concentration. Which of the following could be the structural formula of the hydrocarbon?


AI and II only
B I and III only
C II and IV only
D III and IV only

Which of the following matches is/are correct?


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