A 50 kg sphere is projected vertically upwards with a speed of $$ 200 ms^{-1} $$ . It rises to a height of 1500m. The energy used up in overcoming the friction is

$$ 2.65 \times 10^{5} J $$

$$ 5.6 \times 10^{5} J $$

20 J

Zero

A circular disc is rotating about its own axis. An external opposing torque of magnitude $$ 0.02 Nm $$ is applied on the disc, due to which it comes to rest in $$ 5 $$ seconds. The initial angular momentum of the disc is

0.1 $$ kgm^{2}s^{-1} $$

0.04 $$ kgm^{2}s^{-1} $$

0.025 $$ kgm^{2}s^{-1} $$

0.01 $$ kgm^{2}s^{-1} $$

The work done in rotating the magnet from the direction of uniform field to the opposite direction to the field is $$ W $$ . The work done in rotating the magnet from the field direction to half the maximum couple position is

$$ 2W $$

$$ \frac{\sqrt{3}W}{2} $$

$$ \frac{W}{4}(2-\sqrt{3}) $$

$$ \frac{W}{4}(1-\sqrt{3}) $$

The nuclei $$ _{6}C^{13} $$ and $$ _{7}N^{14} $$ can be described as

Isotones

Isobars

Isomers

Isotopes

In Young's experiment the wavelength of red light is $$ 7.5 \times 10^{-5} $$ cm and that of blue light is $$ 5.0 \times 10^{-5} $$ cm. The value of $$ n $$ for which $$ (n+1) $$ th blue bright band coincides with $$ n $$ th red band, is

8

4

2

1

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