JEE
Gunjan Mehra asked • 9 minutes agoHydrogen 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?
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
What is the value of npo- a)zero
- b)1
- c)n
- d)n!
Correct answer is option 'B'. Can you explain this answer?
What is the value of npo
a)
zero
b)
1
c)
n
d)
n!
Ankita Das answered • 5 hours agoN!/(n-0)!= 1
Sukriti Sharma asked • 19 minutes agoThe intersection of the spheresx2 + y2 + z2 + 7x - 2y - z = 13 and x2 + y2 + z2 -3x + 3y + 4z = 8is 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?
The intersection of the spheres
x2 + y2 + z2 + 7x - 2y - z = 13 and x2 + y2 + z2 -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
Mahender Singh asked • 23 minutes agoIn 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?
a)
720
b)
240
c)
120
d)
36
Nityanand asked • 23 minutes agoFind 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.- 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?
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
Shri Ram asked • 23 minutes agoEach of the following questions consists of five Problem figures marked 1,2,3,4 and 5 followed by five Answer figures marked A,B,C,D and E . Select a figure from the Answer figures which will continue the same series as given in the Problem figures.
- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
Each of the following questions consists of five Problem figures marked 1,2,3,4 and 5 followed by five Answer figures marked A,B,C,D and E . Select a figure from the Answer figures which will continue the same series as given in the Problem figures.
a)
b)
c)
d)
Braham Parkash asked • 35 minutes agoA 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?
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
Shubham Rajput asked • 47 minutes agoThe parabolas y2 = 4x and x2 = 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?
The parabolas y2 = 4x and x2 = 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
Megha Gupta asked • 48 minutes agoTwo 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?
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
Shubham Gupta asked • 52 minutes agoCarbylamine 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?
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
Harsh Kumar asked • 1 hour agoA 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?
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.
Akhil Goyal asked • 2 hours ago
- a)
- b)
- c)tan α
- d)
Correct answer is option 'A'. Can you explain this answer?
a)
b)
c)
tan α
d)
Sarbjit Kaur asked • 2 hours agoA 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?
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)
Kura Bisai asked • 3 hours agoThe 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 n2 to n1 state, the number of lines in the spectrum will be equal to 
If the electron comes back from energy level having energy E2 to energy level having energy E1, 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 × 107 m-1)Q.In a collection of H–atom, electrons make transition from 5th excited state to 2nd excited state then maximum number of different types of photons observed are :... more
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 n2 to n1 state, the number of lines in the spectrum will be equal to
If the electron comes back from energy level having energy E2 to energy level having energy E1, 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 × 107 m-1)
. 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 n2 to n1 state, the number of lines in the spectrum will be equal to If the electron comes back from energy level having energy E2 to energy level having energy E1, 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 × 107 m-1)
Q.
In a collection of H–atom, electrons make transition from 5th excited state to 2nd excited state then maximum number of different types of photons observed are :
Shubham Gupta asked • 3 hours agoIn 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?
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
Sultan Singh asked • 3 hours agoTwo 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?
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
(1, 3) and (82, 30) are vertices of
Then
Raj Bala asked • 4 hours agoA steel rail of length 5 m and area of cross-section 40cm2 is prevented from expanding along its length while the temperature rises by 10oC. If coefficient of linear expansion and Young’s modulus of steel are 1.2×10−5 K−1 and 2×1011 Nm−2 respectively, the force developed in the rail is approximately :- a)2×107 N
- b)1×105 N
- c)2×109 N
- d)3×10−5 N
Correct answer is option 'B'. Can you explain this answer?
A steel rail of length 5 m and area of cross-section 40cm2 is prevented from expanding along its length while the temperature rises by 10oC. If coefficient of linear expansion and Young’s modulus of steel are 1.2×10−5 K−1 and 2×1011 Nm−2 respectively, the force developed in the rail is approximately :
a)
2×107 N
b)
1×105 N
c)
2×109 N
d)
3×10−5 N
, x ∈ R, then the equation f(x) = 0 has:
and 
, then the number of subsets of the set A × B, is :
Akshya Tiwari asked • 5 hours agoA 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- 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?
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
Hashmita Shabbi asked • 5 hours agoIf 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)(x2 + y2)2 = 4Rx2y2
- b)(x2 + y2)(x + y) = R2xy
- c)(x2 + y2)3 = 4R2x2y2
- d)(x2 + y2)2 = 4R2x2y2
Correct answer is option 'C'. Can you explain this answer?
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)
(x2 + y2)2 = 4Rx2y2
b)
(x2 + y2)(x + y) = R2xy
c)
(x2 + y2)3 = 4R2x2y2
d)
(x2 + y2)2 = 4R2x2y2
then the sides a, b, c are in
Deepak Kumar Anand asked • 6 hours agoThe 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−1K−1)- a)a
- b)b
- c)c
- d)d
Correct answer is '25'. Can you explain this answer?
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 .
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−1K−1)
a)
a
b)
b
c)
c
d)
d
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