Forum

nikhil04
@nikhil04
Noble Member
Joined: Aug 19, 2020
Last seen: Jan 13, 2022
Topics: 0 / Replies: 1353
Reply
Answer to: An acidic buffer is obtained on mixing :

Correct answer: (3) 100 mL of 0.1 M HCl and 200 mL of 0.1 M CH3COONa Explanation: Mixture of weak acid and its salt with strong base acts as buffe...

5 years ago
Forum
Reply
Answer to: Tyndall effect is observed when: (1) The diameter of dispersed particles is similar to the wavelength of light used.

Correct answer: (1) The diameter of dispersed particles is similar to the wavelength of light used. Explanation: The diameter of the dispersed par...

5 years ago
Forum
Reply
Answer to: Let CNaCl and CBaSO4 be the conductances (in S) measured for saturated aqueous solutions of NaCl and BaSO4 respectively, at a temperature T.

Correct answer: (1) Ionic mobilities of ions from both salts increase with T. Explanation: (i) Ionic mobilities decrease with increase in temperat...

5 years ago
Forum
Reply
Answer to: It is true that: (1) A first-order reaction is always a single step reaction

Correct answer: (4) A zero-order reaction is a multi step reaction Explanation: Zero order reaction is always multi step reaction.

5 years ago
Forum
Reply
Answer to: Thermal power plants can lead to:

Correct answer: (2) Acid rain Explanation: burning of fossil fuels (which contain sulphur and nitrogenous matter) such as coal and oil in power st...

5 years ago
Forum
Reply
Answer to: The atomic number of the element unnilennium is :

Correct answer: (2) 109 Explanation: un = 1 nil = 0 enn = 9 So Atomic number = 109

5 years ago
Forum
Reply
Answer to: When an object is kept at a distance of 30 cm from a concave mirror, the image is formed at a distance of 10cm from the mirror.

Correct answer: (4) -1 Explanation: Velocity of image vi = - v2/u2 x v0 = - 102/302(9) = -1 cm/sec

5 years ago
Forum
Reply
Answer to: Which of the following will NOT be observed when a multimeter (operating in resistance measuring mode) probes connected across

Correct answer: (3) Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the chosen component is capacitor.

5 years ago
Forum
Reply
Answer to: Two sources of light emit X-rays of wavelength 1 nm and visible light of wavelength 500 nm, respectively.

Correct answer:(2) 1/500 Explanation: Ps - Power of source Ps = n hc/λ ; n = no. of photons emitted /s => n ∝ λ => n2/n1 = λ2/λ1 = 1/500

5 years ago
Forum
Reply
5 years ago
Forum
Reply
Answer to: If a semiconductor photodiode can detect a photon with a maximum wavelength of 400 nm, then its band gap energy is:

Correct answer:(4) 3.1 eV Explanation: λ = 400 nm Band gap Eg = hc/λ = 1237.5/400 = 3.09 eV

5 years ago
Forum
Reply
Answer to: Hydrogen ion and singly ionized helium atom are accelerated, from rest, through the same potential difference.

Correct answer: (1) 1 : 2 Explanation: qV = 1/2mv2 Hence v ∝1/√m vH/vHe = √4/1 = 2 : 1

5 years ago
Forum
Reply
5 years ago
Forum
Reply
Answer to: A calorimeter of water equivalent 20 g contains 180 g of water at 25°C. 'm' grams of steam at 100°C is mixed

Correct answer: (1) 2 Explanation: (200) (31 – 25) = m × 540 + m(1) (69) 1200 = m(609) m ≈ 2

5 years ago
Forum
Reply
Answer to: A block of mass 1.9 kg is at rest at the edge of a table, of height 1 m.

Correct answer: (1) 21 J Explanation: Conservation of linear momentum 0.1 × 20 = (0.1 + 1.9) × v v = 1 m/s Using work energy theorem Wg = Δk...

5 years ago
Forum
Reply
5 years ago
Forum
Reply
Answer to: Two isolated conducting spheres S1 and S2 of radius 2/3R and 1/3 R have 12μC and –3μC charges, respectively

Correct answer: (1) 6 μC and 3μC Explanation: Total charge = 12 – 3 = 9μC If final charges are q1 and q2 q1/q2 = R1/R2 = 2/1 q1 = 6 μC q2 ...

5 years ago
Forum
Reply
Answer to: In Young's double slit experiment, light of 500 nm is used to produce and interference pattern.

Correct answer: (3) 0.57º Explanation: β0 = λ/d = 500 x 10-9/5 x 10-5 = 10-2 Radian = 0.57º

5 years ago
Forum
Reply
Answer to: Using screw gauge of pitch 0.1 cm and 50 divisions on its circular scale, the thickness of an object is measured.

Correct answer: (1) 2.124 cm Explanation: Thickness = M.S. Reading + Circular Scale Reading (L.C.) Here, LC = 0.1/50 = 0.002 cm per division

5 years ago
Forum
Page 8 / 68

How Can We Help?