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Physics · PYQ NEET UG 2018
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Physics · PYQ NEET UG 2018
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length of the first wire is increased by \( \Delta l \) on applying a force F, how much force is needed to stretch the second wire by the same amount?
Read answer →Physics · PYQ NEET UG 2018
The power radiated by a black body is \( P \) and it radiates maximum energy at wavelength, \( \lambda_0 \). If the temperature of the black body is now changed so that it radiates maximum energy at wavelength \( \frac{3}{4}\lambda_0 \), the power radiated by it becomes \( nP \). The value of \( n \) is
Read answer →Physics · PYQ NEET UG 2018
A student measured the diameter of a small steel ball using a screw gauge of least count \( 0.001\text{ cm} \). The main scale reading is \( 5\text{ mm} \) and zero of circular scale division coincides with \( 25 \) divisions above the reference level. If screw gauge has a zero error of \( -0.004\text{ cm} \), the correct diameter of the ball is
Read answer →Physics · PYQ NEET UG 2018
The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is \( 20\text{ cm} \), the length of the open organ pipe is
Read answer →Physics · PYQ NEET UG 2018
In the circuit shown in the figure, the input voltage \( V_i \) is \( 20\text{ V} \), \( V_{\text{BE}} = 0 \) and \( V_{\text{CE}} = 0 \). The values of \( I_{\text{B}} \), \( I_{\text{C}} \) and \( \beta \) are given by
Read answer →Physics · PYQ NEET UG 2018
A body initially at rest and sliding along a frictionless track from a height h (as shown in the figure) just completes a vertical circle of diameter \( AB = D \). The height h is equal to
Read answer →Physics · PYQ NEET UG 2018
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is
Read answer →Physics · PYQ NEET UG 2018
A carbon resistor of \( (47 \pm 4.7)\text{ k}\Omega \) is to be marked with rings of different colours for its identification. The colour code sequence will be
Read answer →Physics · PYQ NEET UG 2018
The refractive index of the material of a prism is \( \sqrt{2} \) and the angle of the prism is \( 30^\circ \). One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is
Read answer →Physics · PYQ NEET UG 2018
An inductor \( 20 \text{ mH} \), a capacitor \( 100 \mu\text{F} \) and a resistor \( 50 \Omega \) are connected in series across a source of emf, \( V = 10 \sin 314 t \). The power loss in the circuit is
Read answer →Physics · PYQ NEET UG 2018
A small sphere of radius 'r' falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to
Read answer →Physics · PYQ NEET UG 2018
When the light of frequency \( 2 u_0 \) (where \( u_0 \) is threshold frequency), is incident on a metal plate, then the maximum velocity of electrons emitted is \( v_1 \). When the frequency of the incident radiation is increased to \( 5 u_0 \), the maximum velocity of electrons emitted from the same plate is \( v_2 \). The ratio of \( v_1 \) to \( v_2 \) is
Read answer →Physics · PYQ NEET UG 2018
Which one of the following statements is incorrect?
Read answer →Physics · PYQ NEET UG 2018
A metallic rod of mass per unit length \( 0.5\text{ kg m}^{-1} \) is lying horizontally on a smooth inclined plane which makes an angle of \( 30^\circ \) with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction \( 0.25\text{ T} \) is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is
Read answer →Physics · PYQ NEET UG 2018
A tuning fork is used to produce resonance in a glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperature of \( 27 ^\circ\text{C} \) two successive resonances are produced at \( 20 \text{ cm} \) and \( 73 \text{ cm} \) of column length. If the frequency of the tuning fork is \( 320 \text{ Hz} \), the velocity of sound in air at \( 27 ^\circ\text{C} \) is
Read answer →Physics · PYQ NEET UG 2018
A block of mass \( m \) is placed on a smooth inclined wedge ABC of inclination \( \theta \) as shown in the figure. The wedge is given an acceleration 'a' towards the right. The relation between a and \( \theta \) for the block to remain stationary on the wedge is
Read answer →Physics · PYQ NEET UG 2018
In Young's double slit experiment the separation \( d \) between the slits is \( 2\text{ mm} \), the wavelength \( \lambda \) of the light used is \( 5896\text{ \AA} \) and distance \( D \) between the screen and slits is \( 100\text{ cm} \). It is found that the angular width of the fringes is \( 0.20^\circ \). To increase the fringe angular width to \( 0.21^\circ \) (with same \( \lambda \) and \( D \)) the separation between the slits needs to be changed to
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The moment of the force, \( \vec{F} = 4\hat{i} + 5\hat{j} - 6\hat{k} \) at \( (2, 0, -3) \), about the point \( (2, -2, -2) \), is given by
Read answer →Physics · PYQ NEET UG 2018
An em wave is propagating in a medium with a velocity \( \vec{v} = v\hat{i} \). The instantaneous oscillating electric field of this em wave is along \( + \text{Y} \) axis. Then the direction of oscillating magnetic field of the em wave will be along
Read answer →Physics · PYQ NEET UG 2018
