Mansi Behl asked • 1 minute ago

According to Bohr’s theory, the time averaged magnetic field at the centre (i.e. nucleus) of a hydrogen atom due to the motion of electrons in the n^{th} orbit is proportional to : (n=principal quantum number)

- a)n
^{−4} - b)n
^{−5} - c)n
^{−3} - d)n
^{−2}

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

Mansi Behl asked • 27 minutes ago

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-

Assertion(A): If P(2a,0) be any point on the axis of parabola, then the chord QPR, satisfies

Reason(R): There exists a point on the axis of the parabola y^{2} = 4ax such that = constant for all chords QPR of the parabola.

Assertion(A): If P(2a,0) be any point on the axis of parabola, then the chord QPR, satisfies

Reason(R): There exists a point on the axis of the parabola y

- a)Both Assertion and Reason are true and Reason is the correct explanation of assertion.
- b)Both Assertion and Reason are true and Reason is not the correct explanation of assertion.
- c)Assertion is true but Reason is false.
- d)Assertion is false but Reason is true.

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

Mansi Behl asked • 34 minutes ago

A spherical metal shell A of radius R_{A} and a solid metal sphere B of radius R_{B} (<R_{A}) are kept far apart and

each is given charge ‘+Q’. Now they are connected by a thin metal wire. Then

each is given charge ‘+Q’. Now they are connected by a thin metal wire. Then

- a)
- b)Q
_{A}> Q_{B} - c)
- d)

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

Sudeep Das asked • 36 minutes ago

A tube of length L is filled completely with an incompressible liquid of mass M and closed at both the ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity ω. The force exerted by the liquid at the other end is

- a)MLω
^{2}/2 - b)MLω
^{2} - c)MLω
^{2}/4 - d)ML
^{2}ω^{2}/2

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

Mansi Behl asked • 40 minutes ago

The initial speed of a bullet fired from a rifle is 630 m/s. The rifle is fired at the centre of a target 700 m away at the same level as the target. How far above the centre of the target the rifle must be aimed in order to hit the target

- a)4.2 m
- b)6.1 m
- c)1.0 m
- d)9.8 m

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

Mansi Behl asked • 49 minutes ago

=

- a)
- b)3
- c)3
- d)none

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

Mansi Behl asked • 1 hour ago

A single slit of width b is illuminated by a coherent monochromatic light of wavelength λ. If the second and fourth minima in the diffraction pattern at a distance 1 m from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum? (i.e. distance between first minimum on either side of the central maximum)

- a)1.5 cm
- b)3.0 cm
- c)4.5 cm
- d)6.0 cm

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

Varad Rane asked • 1 hour ago

Q. The fringe width β can be expressed as

- a)β=β
_{0}sinωt - b)β=β
_{0}sin2ωt - c)β=β
_{0}cosωt - d)none of these

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

Puran Singh asked • 2 hours ago

Let a, b and λ be positive real numbers. Suppose P is an end point of the latus rectum of the parabola y^{2} = 4λx, and suppose the ellipse passes through the point P. If the tangents to the parabola and the ellipse at the point P are perpendicular to each other, then the eccentricity of the ellipse is

- a)1/√2
- b)1/2
- c)1/3
- d)2/5

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

Mansi Behl asked • 2 hours ago

In the circuit diagrams (A, B, C, and D) shown below, R is a high resistance and S is a resistance the order of galvanometer G. The correct circuit, corresponding to the half deflection method for finding the resistance and figure of merit of the galvanometer, is the circuit labelled as:

- a)Circuit C with G = S
- b)Circuit B with G = S
- c)Circuit A with
- d)Circuit D with

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

Mansi Behl asked • 2 hours ago

In Young’s double slit experiment, the distance between slits and the screen is 1.0 m and monochromatic light of 600 nm is being used. A person standing near the slits is looking at the fringe pattern. When the separation between the slits is varied, the interference pattern disappears for a particular distance d0 between the slits. If the angular resolution of the eye is 1º/60 the value of d_{0} is close to :

- a)1mm
- b)2mm
- c)4mm
- d)3mm

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

Mansi Behl asked • 2 hours ago

In 1906, Robert Millikan devised an experiment that allowed him to determine the charge of an electron. A schematic of Millikan’s set – up is shown below:

Two metal plates are connected by a series of batteries to form a capacitor. There is an electric field between the plates. The metal plates are inside an insulated cylindrical container.

Oil drops are introduced into the container through a small hole in the top. The oil drops acquire a negative charge as they pass through the nozzle of the oil can. Some of the drops fall through a hole in the upper plate. By adjusting the voltage between the plates, certain drops can be suspended between them. The relationship between the electric field between the plates and the voltage across the plates is ∆V = EL

Where E is the electric field and L is the plate separation.

Millikan chose oil because of its relatively low vapour pressure and high charge holding ability. (To answer the following question assume oil drops as to be non-conducting tiny spheres)

Two metal plates are connected by a series of batteries to form a capacitor. There is an electric field between the plates. The metal plates are inside an insulated cylindrical container.

Oil drops are introduced into the container through a small hole in the top. The oil drops acquire a negative charge as they pass through the nozzle of the oil can. Some of the drops fall through a hole in the upper plate. By adjusting the voltage between the plates, certain drops can be suspended between them. The relationship between the electric field between the plates and the voltage across the plates is ∆V = EL

Where E is the electric field and L is the plate separation.

Millikan chose oil because of its relatively low vapour pressure and high charge holding ability. (To answer the following question assume oil drops as to be non-conducting tiny spheres)

Suppose the original oil droplet were replaced with a positively charged one that had twice the charge and three times the mass of the original droplet, how would the magnitude of the electric field have to be changed in order for the drop to remain suspended?

Suman Kaur asked • 3 hours ago

A particle of mass 'm' original at rest, is subjected to a force whose direction is constant but whose magnitude varies with according to the relation

,Where F_{0} and T are constant.

Then speed of the particle after a time 2T is:

,Where F

Then speed of the particle after a time 2T is:

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

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

Mansi Behl asked • 3 hours ago

A block of mass 0.1 kg is connected to an elastic spring of spring constant 640 Nm^{−1} and oscillates in a damping medium of damping constant 10^{−2} kg s^{−1}. The system dissipates its energy gradually. The time taken for its mechanical energy of vibration to drop to half of its initial value, is closest to :

- a)2 s
- b)3.5 s
- c)5 s
- d)7 s

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

Karan asked • 3 hours ago

Can you explain the answer of this question below:

Two tangent galvanometers having coils of the same radius are connected in series. A current flowing in them produces deflections of 60^{o} and 45^{o}respectively. The ratio of the number of turns in the coils is

- A:
4/3

- B:
(√3+1)/1

- C:
√3+1/√3-1

- D:
√3/1

- E:
undefined

The answer is d.

Mansi Behl asked • 3 hours ago

A charged particle moving in a magnetic field experiences a resultant force

- a)in a direction of magnetic field
- b)in the direction opposite to the magnetic field
- c)in the direction perpendicular to both the magnetic field and its velocity
- d)none of the above

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

Mishika Jaiswal asked • 3 hours ago

Which of the following statements is correct

- a)The stopping potential increases with increasing intensity of incident light
- b)The photocurrent increases with increasing intensity of light
- c)The photocurrent is proportional to applied voltage
- d)The current in a photocell increases with increasing frequency of light

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

Mansi Behl asked • 3 hours ago

Time (T), velocity (C) and angular momentum (h) are chosen as fundamental quantities instead of mass, length and time. In terms of these, the dimensions of mass would be :

- a)[M ]=[ T
^{−1}C^{−2}h] - b)[M]=[T
^{−1}C^{2}h] - c)[M]=[T
^{−1}C^{−2 }h^{−1}] - d)[M]=[T C
^{−2}h]

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

Mansi Behl asked • 4 hours ago

A particle starts from rest and has an acceleration of 2m − s⁻^{2} for 10 s. After that, it travels for 30 s with constant speed and then undergoes a retardation of 4 m − s⁻^{2} and comes back to rest. The total distance covered by the particle is

- a)650 m
- b)700 m
- c)750 m
- d)800 m

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

Jeeva Anchitha asked • 4 hours ago

Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii R_{1} and R_{2} respectively. The ratio of the mass of X to that of Y is

- a)(R
_{1}/R_{2}) - b)(R
_{2}/R_{1}) - c)(R
_{1}/R_{2})^{1/2} - d)(R
_{1}/R_{2})^{2}

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

Krishna Prajapati asked • 4 hours ago

Let a_{1}, a_{2}, a_{3}, ….. be a sequence of positive integers in arithmetic progression with common difference 2. Also, let b_{1}, b_{2}, b_{3}, ….. be a sequence of positive integers in geometric progression with common ratio 2. If a_{1} = b_{1} = c, then the number of all possible values of c, for which the equality 2(a_{1} + a_{2} + ….+a_{n} ) = b_{1} + b_{2} + ….. + b_{n} holds for some positive integer n, is ______

Correct answer is '1.00'. Can you explain this answer?

Mohan Singh asked • 4 hours ago

Let C_{1} and C_{2} be two biased coins such that the probabilities of getting head in a single toss are 2/3 and 1/3, respectively. Suppose α is the number of heads that appear when C_{1} is tossed twice, independently, and suppose β is the number of heads that appear when C_{2} is tossed twice, independently, Then probability that the roots of the quadratic polynomial x^{2} – αx + β are real and equal, is

- a)40/81
- b)20/81
- c)1/2
- d)1/4

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

Danish Wajahath Wajahath asked • 4 hours ago

A circular coil of radius R and N turns has negligible resistance. As shown in the schematic figure, its two ends are connected to two wires and it is hanging by those wires with its plane being vertical. The wires are connected to a capacitor with charge Q through a switch. The coil is in a horizontal uniform magnetic field B_{o} parallel to the plane of the coil. When the switch is closed, the capacitor gets discharged through the coil in a very short time. By the time the capacitor is discharged fully, magnitude of the angular momentum gained by the coil will be (assume that the discharge time is so short that the coil has hardly rotated during this time)-

- a)(π/2)NQB
_{o}R^{2} - b)πNQB
_{o}R^{2} - c)2πNQB
_{o}R^{2} - d)4πNQB
_{o}R^{2}

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

Gajula Deepak asked • 5 hours ago

- a)1 : 4
- b)1 : 2
- c)2 : 1
- d)4 : 1

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

Khushi Matariya asked • 5 hours ago

Mansi Behl asked • 5 hours ago

In the set W of whole numbers an equivalence relation R is defined as follows :

aRb iff both a and b leave same remainder when divided by 5. The equivalence class of 1 is given by

aRb iff both a and b leave same remainder when divided by 5. The equivalence class of 1 is given by

- a){0, 5, 10, 15, ...}
- b){1, 6, 11, 16, ...}
- c){2, 7, 12, 17, ...}
- d){4, 9, 14, 19, ...}

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

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