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A block of mass \(m_{2}\) is placed on a horizontal table and another block of mass \(m_{1}\) is placed on top of it. An increasing horizontal force \(F=\alpha t\) is exerted on the upper block but the lower block never moves as a result. If the co-efficient of friction between the blocks is \(\mu_{1}\) and that between the lower block and the table is \(\mu_{2}\), then what is the maximum possible value of \(\mu_{1} / \mu_{2}\) ?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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In case of a simple harmonic motion, if the velocity is plotted along the X-axis and the displacement (from the equilibrium position) is plotted along the Y-axis, the resultant curve happens to be an ellipse with the ratio: \(\frac{\text { major axis (along X) }}{\text { min or axis (along Y) }}=20 \pi\) What is the frequency of the simple harmonic motion ?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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An electron accelerated through a potential of \(10,000 \mathrm{~V}\) from rest has a de-Broglie wave length ' \(\lambda\) '. What should be the accelerating potential so that the wave length is doubled?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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If the half life of a radioactive nucleus is 3 days, nearly what fraction of the initial number of nuclei will decay on the \(3^{\text {rd }}\) day? (Given that \(\sqrt[3]{0.25} \approx 0.63\) )

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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How the linear velocity 'v' of an electron in the Bohr orbit is related to its quantum number ' \(n\) ' ?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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If Young's double slit experiment is done with white light, which of the following statements will be true?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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There is a small air bubble at the centre of a solid glass sphere of radius ' \(r\) ' and refractive index ' \(\mu\) '. What will be the apparent distance of the bubble from the centre of the sphere, when viewed from outside ?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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A point source is placed at co-ordinates \((0,1)\) in \(X-Y\) plane. A ray of light from the source is reflected on a plane mirror placed along the X-axis and perpendicular to the X-Y plane. The reflected ray passes through the point \((3,3)\). What is the path length of the ray from \((0,1)\) to \((3,3)\) ?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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Four resistors \(100 \Omega, 200 \Omega, 300 \Omega\) and \(400 \Omega\) are connected to form four sides of a square. The resistors can be connected in any order. What is the maximum possible equivalent resistance across the diagonal of the square ?

asked Dec 12, 2021 in Kinematics by kritika (90.1k points)

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A charged particle moves with constant velocity in a region where no effect of gravity is felt but an electrostatic field \(\vec{E}\) together with a magnetic field \(\vec{B}\) may be present. Then which of the following cases are possible ?

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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A \(400 \Omega\) resistor, a \(250 \mathrm{mH}\) inductor and a \(2.5 \mu \mathrm{F}\) capacitor are connected in series with an \(\mathrm{AC}\) source of peak voltage \(5 \mathrm{~V}\) and angular frequency \(2 \mathrm{kHz}\). What is the peak value of the electrostatic energy of the capacitor?

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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A simple pendulum of length \(\ell\) is displaced so that its taught string is horizontal and then released. A uniform bar pivoted at one end is simultaneously released from its horizontal position. If their motions are synchronous, what is the length of the bar?

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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Two metallic spheres of equal outer radii are found to have same moment of inertia about their respective diameters. Then which of the following statement(s) is/are true ?

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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A point source of light is used in an experiment of photo-electric effects. If the distance between the source and the }{ photo-electric surface is doubled, which of the following may result? }

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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Two pith balls, each carrying charge \(+q\) are hung from a hook by two strings. It is found that when each charge is tripled, angle between the strings double. What was the initial angle between the strings ?

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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Consider an engine that absorbs 130 cal of heat from a hot reservoir and delivers 30 cal heat to a cold reservoir in each cycle. The engine also consumes \(2 \mathrm{~J}\) energy in each cycle to overcome friction. If the engine works at 90 cycles per minute, what will be the maximum power delivered to the load? [Assume the thermal equivalent of heat is \(4.2 \mathrm{~J} / \mathrm{cal}\) ]

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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A pair of parallel metal plates are kept with a separation ' \(\mathrm{d}\) '. One plate is at a potential \(+\mathrm{V}\) and the other is at ground potential. A narrow beam of electrons enters the space between the plates with a velocity \(v_{0}\) and in a direction parallel to the plates. What will be the angle of the beam with the plates after it travels an axial distance L?

asked Dec 11, 2021 in Magnetic effects of by kritika (90.1k points)

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A conducting circular loop of resistance \(20 \Omega\) and cross-sectional area \(20 \times 10^{-2} \mathrm{~m}^{2}\) is placed perpendicular to a spatially uniform magnetic field \(B\), which varies with time \(t\) as \(B=2 \sin (50 \pi t) T\). Find the net charge flowing through the loop in \(20 \mathrm{~ms}\) starting from \(\mathrm{t}=0\)

asked Dec 11, 2021 in Magnetic effects of by kritika (90.1k points)

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A thin convex lens is placed just above an empty vessel of depth \(80 \mathrm{~cm}\). The image of a coin kept at the bottom of the vessel is thus formed \(20 \mathrm{~cm}\) above the lens. If now water is poured in the vessel up to a height of \(64 \mathrm{~cm}\), what will be the approximate new position of the image. Assume that refractive index of water is \(4 / 3 .\)

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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An object is placed \(60 \mathrm{~cm}\) in front of a convex mirror of focal length \(30 \mathrm{~cm}\). A plane mirror is now placed facing the object in between the object and the convex mirror such that it covers lower half of the convex mirror. What should be the distance of the plane mirror from the object so that there will be no parallax between the images formed by the two mirrors?

asked Dec 11, 2021 in Kinematics by kritika (90.1k points)

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