Which one of the following statements is incorrect?
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A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field $\vec{E}$ Due to the force q $\vec{E}$ E , its velocity increases from 0 to 6 m/s in one second duration. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between 0 to 3 seconds are respectively |
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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 |
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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 |
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A student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 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 cm, the correct diameter of the ball is |
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A solid sphere is rotating freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere? |
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The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are $K_{A}, K_{B}$ and $K_{C}$, respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then |
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If the mass of the Sun were ten times smaller and the universal gravitational constant were ten times larger in magnitude, which of the following is not correct? |
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A solid sphere is in rolling motion. In rolling motion a body possesses translational kinetic energy $\left(K_{t}\right)$ as well as rotational kinetic energy $\left(K_{t}\right)$ simultaneously. The ratio $K_{t}:\left(K_{t}+K_{r}\right)$ for the sphere is |
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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 |
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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 $\dfrac{3}{4}\lambda_0$, 4 the power radiated by it becomes nP. The value of n is |
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