It’s Sunday 🙂 and time for our Weekly Exams Questions with Solution.
Every week from Monday to Thursday, we post questions (Biology, Chemistry, Physics and Mathematics) on our social media learning platforms for the preparation of several examinations like JEE Main, JEE Advanced, BITSAT, AIPMT, AIIMS, State PMT, KVPY, NTSE, Olympiads.
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(Update : From 2016, we are no longer posting regular questions on social platforms.)
Questions and answers from this week,
Biology Questions (Posted on Monday, September 28, 2015)
Q 1. The upright pyramid of number is absent in [For AIPMT Preparation]
Answer: b) Forest
Q 2. Electron beam therapy is a kind of radiation therapy to treat [For AIIMS Preparation]
a) Enlarged prostate gland
b) Gall bladder stones by breaking them
c) Certain types of cancer
d) Kidney stones
Answer: c) Certain types of cancer
Electron beam therapy is used in the treatment of superficial tumors like cancer of skin regions.
Chemistry Questions (Posted on September 29, 2015)
Q 1. Which is the main function of RBC? [For NTSE SAT Stage-1 Preparation]
a) To fight diseases in the body
b) To carry oxygen to different parts of the body
c) To increase levels of WBC
d) To arrest bleeding
Answer: b) To carry oxygen to different parts of the body
Q 2. Which of the following rotation of crops will reduce dependence on the use of chemical fertilizers? [For NTSE SAT Stage-1 Preparation]
a) Rice and Chilli
b) Wheat and Potato
c) Potato and Rice
d) Gram and Rice
Answer: d) Gram and Rice
Crops like pulses, beans, gram, all these are leguminous crops. When the cereal crops like rice or wheat are grown in the soil, it uses up a lot of nitrogenous salts from the soil. If another crop of cereal is grown in the same soil, the soil becomes nitrogen deficient. So by rotation a leguminous crop is grown. There plants have the ability to fix atmospheric nitrogen to form nitrogen compounds through the help of certain bacteria present in their root. These nitrogen compounds go into the soil and make it more fertile. So it reduces the dependence of using chemical fertilizers.
Physics Questions (Posted on September 30, 2015)
Q 1. The maximum attraction in a magnet is : [For NTSE Preparation]
a) In the centre
b) On the sides
c) On the poles
d) On the surface
Answer: c) On the poles
Q 2. The expansion of a solid body depends on [For NTSE SAT Preparation]
a) Mass of the solid only
b) Nature of the solid only
c) Temperature of the solid only
d) Nature and temperature of the solid
Answer: d) Nature and temperature of the solid
Mathematics Questions (Posted on October 1, 2015)
Q 1. The decimal expansion of π (pi) is : [NTSE Mathematics]
a) a whole number
c) non-terminating but repeating
d) non-terminating but non-repeating
Answer: d) non-terminating but non-repeating
Q 2. A pair of equations x = a and y = b graphically represent lines which are : [NTSE Stage1 Mathematics]
a) intersecting at (a, b)
b) intersecting at (b, a)
Answer: a) intersecting at (a, b)
Bonus Organic Chemistry Question (Asked by a student of class 11th)
Question: 0.4422 g of an organic compound was Kjeldahlised and ammonia evolved was absorbed in 50 ml of 0.5 M H2SO4. The residual acid required 131 ml of 0.25 M NaOH. Determine the % of Nitrogen.
Solution: Total volume of the solution = 50 ml (H2SO4, 0.5 M)
Let x be the volume of 0.5 M H2SO4 neutralized by 131 ml NaOH of of 0.25 M.
[Normality = Molarity x V.F]
Therefore, 0.5 M H2SO4 = 1 N H2SO4
0.25 M NaOH = 0.25 N H2SO4
From Normality equation,
N1V1 = N2V2
1 x V1 = 131 x 0.25
V1 = 32.75 ml
i.e. 32.75 ml solution of 1 N H2SO4 is neutralized by 0.25 N NaOH
Then remaining solution which absorbed Ammonia = 50 ml – 32.75 ml = 17.25 ml of H2SO4
% of Nitrogen = 1.4 x Normality of the acid x Volume of acid / Mass of organic compound
= 1.4 x 1 N x 17.25 / 0.4422 = 54.61 %.
So, that’s it from this week.
I will see you next Sunday with a new set of questions.
Thanks so much. Take care.