Gunjan Mehra asked • 9 minutes ago

Hydrogen bonding plays a central role in the following phenomena

- a)Ice floats in water
- b)Higher Lewis basicity of primary amines than tertiary amines in aqueous solutions
- c)Formic acid is more acidic than acetic acid
- d)Dimerisation of acetic acid in benzene

Correct answer is option 'A,B,D'. Can you explain this answer?

What is the value of ^{n}p_{o}

- a)zero
- b)1
- c)n
- d)n!

Correct answer is option 'B'. Can you explain this answer?

Ankita Das answered • 5 hours ago

N!/(n-0)!= 1

Sukriti Sharma asked • 19 minutes ago

The intersection of the spheres

x^{2} + y^{2} + z^{2} + 7x - 2y - z = 13 and x^{2} + y^{2} + z^{2} -3x + 3y + 4z = 8

is the same as the intersection of one of the sphere and the plane

- a)2x - y -z = 1
- b)x - 2y - z = 1
- c)x - y -2z = 1
- d)x - y - z = 1

Correct answer is option 'A'. Can you explain this answer?

Mahender Singh asked • 23 minutes ago

In a 12 storey building 3 persons enter a lift cabin. It is known that they will leave the lift at different storeys. In how many ways can they do so if the lift does not stop at the second storey.

- a)720
- b)240
- c)120
- d)36

Correct answer is option 'A'. Can you explain this answer?

Nityanand asked • 23 minutes ago

Find the Synonym of the word occurring in the sentence in capital letter as per the context.

I can no longer be satisfied with FICTITIOUS good conduct.

I can no longer be satisfied with FICTITIOUS good conduct.

- a)based on facts
- b)based on imagination
- c)based on works of fiction
- d)based on feudal ties

Correct answer is option 'C'. Can you explain this answer?

Shri Ram asked • 23 minutes ago

- a)
- b)
- c)
- d)

Correct answer is option 'A'. Can you explain this answer?

Braham Parkash asked • 35 minutes ago

A convex lens is put 10 cm from a light source and it makes a sharp image on a screen, kept 10 cm from the lens. Now a glass block (refractive index 1.5) of 1.5 cm thickness is placed in contact with the light source. To get the sharp image again, the screen is shifted by a distance d. Then d is :

- a)0.55 cm away from the lens
- b)1.1 cm away from the lens
- c)0.55 cm towards the lens
- d)0

Correct answer is option 'A'. Can you explain this answer?

Shubham Rajput asked • 47 minutes ago

The parabolas y^{2} = 4x and x^{2} = 4y divide the square region bounded by the lines x = 4, y = 4 and the coordinate axes. If S₁, S₂, S₃ are respectively the areas of these parts numbered from top to bottom; then S₁ : S₂ : S₃ is

- a)1 : 2 : 3
- b)1 : 2 : 1
- c)1 : 1 : 1
- d)2 : 1: 2

Correct answer is option 'C'. Can you explain this answer?

Megha Gupta asked • 48 minutes ago

Two radioactive materials A and B have decay constants 10λ and λ,respectively . If initially they have the same number of nuclei, then the ratio of the number of nuclei, then the ratio of the number of nuclei of A to that of B will be 1/e after a time

- a)1/9λ
- b)1/11λ
- c)1/10λ
- d)11/10λ

Correct answer is option 'A'. Can you explain this answer?

Shubham Gupta asked • 52 minutes ago

Carbylamine test is performed in alcoholic KOH by heating a mixture of :

- a)chloroform and silver powder
- b)trihalogenatedmethane and a primary amine
- c)an alkyl halide and a primary amine
- d)an alkyl cyanide and a primary amine

Correct answer is option 'B'. Can you explain this answer?

Harsh Kumar asked • 1 hour ago

A parallel plate capacitor is charged using a battery, and the battery is then removed. The plates of the capacitor are then brought closer together. Which of the following statements is false?

- a)The capacitance of the capacitor increases.
- b)The charge on the capacitor remains the same..
- c)The potential difference between the plates of the capacitor decreases.
- d)The energy stored in the capacitor increases.

Correct answer is option 'D'. Can you explain this answer?

Akhil Goyal asked • 2 hours ago

- a)
- b)
- c)tan α
- d)

Correct answer is option 'A'. Can you explain this answer?

Sarbjit Kaur asked • 2 hours ago

A loop of radius R and mass m is placed in a uniform magnetic field B with its plane perpendicular to the field. Current I is flowing in it. Now loop is slightly rotated about its diameter and released. Find time period of oscillation.

- a)
- b)
- c)
- d)

Correct answer is option 'B'. Can you explain this answer?

Kura Bisai asked • 3 hours ago

The only electron in the hydrogen atom resides under ordinary conditions on the first orbit. When energy is supplied, the electron moves to higher energy orbit depending on the amount of energy absorbed. When this electron returns to any of the lower orbits, it emits energy. Lyman series is formed when the electron returns to the lowest orbit while Balmer series is formed when the electron returns to second orbit. Similarly, Paschen, Brackett and Pfund series are formed when electron returns to the third, fourth and fifth orbits from higher energy orbits respectively. Maximum number of lines produced when an electron jumps from nth level to ground level is equal to . For examle, in the case of n = 4, number of lines produced is 6. (4 → 3, 4 → 2, 4 → 1, 3 → 2, 3 → 1, 2 → 1). When an electron returns from n_{2} to n_{1} state, the number of lines in the spectrum will be equal to

If the electron comes back from energy level having energy E_{2} to energy level having energy E_{1}, then the difference may be expressed in terms of energy of photon as :

Since h and c are constants, ΔE corresponds to definite energy; thus each transition from one energy level to another will produce a light of definite wavelength. This is actually observed as a line in the spectrum of hydrogen atom.

Wave number of line is given by the formula

where R is a Rydberg’s constant

(R = 1.1 × 10^{7} m^{-1})

If the electron comes back from energy level having energy E

Since h and c are constants, ΔE corresponds to definite energy; thus each transition from one energy level to another will produce a light of definite wavelength. This is actually observed as a line in the spectrum of hydrogen atom.

Wave number of line is given by the formula

where R is a Rydberg’s constant

(R = 1.1 × 10

Shubham Gupta asked • 3 hours ago

In general, the properties that decrease and increase down a group in the periodic table, respectively, are :

- a)electronegativity and electron gain enthalpy
- b)electronegativity and atomic radius
- c)atomic radius and electronegativity
- d)electron gain enthalpy and electronegativity

Correct answer is option 'B'. Can you explain this answer?

Sultan Singh asked • 3 hours ago

Two cards are drawn successively with replacement from a well-shuffled deck of 52 cards. Let X denote the random variable of number of aces obtained in the two drawn cards. Then P(X = 1) + P(X = 2) eauals :

- a)52/169
- b)25/169
- c)49/169
- d)24/169

Correct answer is option 'B'. Can you explain this answer?

Diksha Indora asked • 3 hours ago

The asymptotes of the curve 2x^{2} + 5xy + 2y^{2} + 4x + 5y = 0 are given by

- a)2x
^{2}+ 5xy + 2y^{2}+ 4x + 5y + 2 = 0 - b)2x
^{2}+ 5xy + 2y^{2}+ 4x + 5y - 2 = 0 - c)2x
^{2}+ 5xy + 2y^{2}+ 4x + 5y - 4 = 0 - d)None of these

Correct answer is option 'A'. Can you explain this answer?

Raj Bala asked • 4 hours ago

A steel rail of length 5 m and area of cross-section 40cm^{2} is prevented from expanding along its length while the temperature rises by 10^{o}C. If coefficient of linear expansion and Young’s modulus of steel are 1.2×10^{−5} K^{−1} and 2×10^{11} Nm^{−2} respectively, the force developed in the rail is approximately :

- a)2×10
^{7}N - b)1×10
^{5}N - c)2×10
^{9}N - d)3×10
^{−5}N

Correct answer is option 'B'. Can you explain this answer?

Akshya Tiwari asked • 5 hours ago

A travelling harmonic wave is represented by the equation y (x, t) = 10^{–3} sin (50 t + 2x), where x and y are in meter and t is in seconds. Which of the following is a correct statement about the wave?

The wave is propagating along the

The wave is propagating along the

- a)negative x-axis with speed 25ms
^{–1} - b)The wave is propagating along the positive x-axis with speed 25 ms
^{–1} - c)The wave is propagating along the positive x-axis with speed 100 ms
^{–1} - d)The wave is propagating along the negative x-axis with speed 100 ms
^{–1}

Correct answer is option 'A'. Can you explain this answer?

Hashmita Shabbi asked • 5 hours ago

If a circle of radius R passes through the origin O and intersects the coordinate axes at A and B, then the locus of the foot of perpendicular from O on AB is :

- a)(x
^{2}+ y^{2})^{2}= 4Rx^{2}y^{2} - b)(x
^{2}+ y^{2})(x + y) = R^{2}xy - c)(x
^{2}+ y^{2})^{3}= 4R^{2}x^{2}y^{2} - d)(x
^{2}+ y^{2})^{2}= 4R^{2}x^{2}y^{2}

Correct answer is option 'C'. Can you explain this answer?

Deepak Kumar Anand asked • 6 hours ago

The vapour pressure of a certain liquid is given by the equation Where P is vapour pressure in mmHg and T is temperature in K. Calculate latent heat of vaporisation (in cal mol^{−1}) at 75 .

K(R=2calmol^{−1}K^{−1})

- a)a
- b)b
- c)c
- d)d

Correct answer is '25'. Can you explain this answer?

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