The acceleration due to gravity g on earth is 9.8 ms ^-2 . What would the value of g for a planet whose size is the same as that of earth but the density in twice that of earth?

1) 19.6 ms^-2
2) 9.8 ms^-2
3) 4.9 ms^-2
4) 2.5 ms^-2

Combination of two identical capacitors, a resistor R and a dc voltage source of voltage 6V is used in an experiment on a (C-R) circuit. It is found that for a parallel combination of the capacitor the time in which the voltage of the fully charged combination reduces to half its original voltage is 10 second. For series combination the time needed for reducing the voltage of the fully charged series combination by half is?

1) 2.5 second

2)  20 second

3) 10 second

4) 5 second

As an object falls freely, the kinetic energy of the object

1) decreases
2) increases
3) remains the same
4) none

Two full terms of the circular scale of a screw gauge cover a distance of 1mm on its main scale. The total number of divisions on the circular scale is 50. Further, it is found that the screw gauge has a zero error of −0.03mm. While measuring the diameter of a thin wire, a student notes the main scale reading of 3mm and the number of circular scale divisions in line with the main scale as 35. The diameter of the wire is

1) 3.32mm
2) 3.73mm
3) 3.67mm
4) 3.38mm

Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?

1) Paschen series
2) Balmer series
3) Lyman series
4) Brackett series

 A pendulum having a period of oscillation of 2 seconds is taken on a planet where g is four times that on the earth. The period of the pendulum would be

1) 4 s

2) 2 s

3) 1 s

4) ½ s

A coil, a capacitor and an AC source of rms voltage 24V are connected in series. By varying the frequency of the source, a maximum rms current of 6A is observed. If coil is connected to a dc battery of emf 12 volt and internal resistance 4Ω, then current through it in steady state is :

1) 2.4A
2) 1.8A
3) 1.5A
4) 1.2A

Consider a drop of rain water having mass 1 g fallingfrom a height of 1 km. It its the ground with a speedof 50 m/s. Take g constant with a value10 m/s². The work done by the (i) gravitational force and the (ii) resistive force of air is

1) (i) – 10 J (ii) –8.25 J
2) (i) 1.25 J (ii) –8.25 J
3) (i) 100 J (ii) 8.75 J
4) (i) 10 J (ii) –8.75 J

Two planets are circling around a distant star. The orbital radius of planet A is half that of planet (2) Which statement is correct?

1) w_A >w_B and v_A > v_B

2) w_A >w_B and v_A  < v_B

3) w_A =w_B and v_A > v_B

4) w_A =w_B and v_A < v_B

The distance to which an electron of a hydrogen atom is to be removed from the atom so that the force of electrostatic attraction is equal to six times the weight of the atom, will be :

[Take g=10 m/s² and number of atoms in 1 kg1 kg of monoatomic hydrogen is 66 x 10²⁶]

1) 1.2 cm

2) 4.8 cm

3) 2.4 cm

4) 3.6 cm