A cube of aluminum has side length 0.10 m. It is dropped into a deep swimming pool of water with density 1.00 x 10³ kg/m³ . The cube comes gently to rest at the bottom of the pool. If the density of the aluminum is 2.7 x 10³  kg/m3 , the magnitude of the buoyant force acting on the aluminum is:

1) 26.6 N
2) 9.8 N
3) 2.7 N
4) 1.0 N

 A cart of mass has a block of mass m attached to it as shown in figure. The coefficient of friction between the block and the cart is µ. What is the minimum acceleration of the cart so that the block m does not fall

1)µg
2) g/µ
3)µ/g
4)Mµg/m

A beam of monochromatic ligh first travels through glass of R.I. 1.5 and then through water (R.I. =4/3). If the difference in their wavelength in the two media is 40nm, then the wavelength of the monochromatic light in vacuum will be

1) 4000 Å
2) 4400 Å
3) 4800 Å
4) 5200 Å 

Light of wavelength $$\displaystyle \lambda $$ from a point source falls on a small circular obstacle of diameter $$'d'$$. Dark and bright circular rings around a central bright spot are formed on a screen beyond the obstacle. The distance between the screen and obstacle is $$D$$. Then, the condition for the formation of rings is:

1) $$\displaystyle \lambda \approx \frac { { d }^{ 2 } }{ 4D } $$
2) $$\displaystyle d\approx \frac { { \lambda }^{ 2 } }{ D } $$
3) $$\displaystyle \lambda \approx \frac { D }{ 4 } $$
4) $$\displaystyle \sqrt { \lambda } =\frac { d }{ 4D } $$

A car travels 90. meters due north in 15 seconds. Then the car turns around and travels 40. meters due south in 5.0 seconds. What is the magnitude of the average velocity of the car during this 20.-second interval?
 
 1) 2.5 m/s
 2) 5.0 m/s
 3) 6.5 m/s
 4) 7.0 m/s

Electric current arises from the flow of charged particles, Now:

(1) In electrolytes, It is mainly due to the flow of negative ions.
(2) In discharge tubes containing gases at low pressure, it is due to the flow of positive ions only
(3) In metals, it is mainly due to the flow of electrons.
(4) In semi-conductors, it is mainly due to the flow of holes.

A wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250 m². Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be: ( ρair=1.2 kg/m³)

1) 4.8×10⁵N, upwards

2) 2.4×10⁵N upwards

3) 4.8×10⁵N downwards

4) None of these

The image of an object placed at 60cm in fromt of a lens is obtained on a screen at a distance of 120 cm from it. Find the local of the lens. what would be the height of the image if the object is 5cm high ?

1)  5cm
2) −10cm
3)  10cm
4) −20cm

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

Two radiations containing photons of energy twice and five times the work function of a metal one incident successively on the metal surface. The ratio of the maximum velocities of the emitted electrons in the two cases will be:

1).1 : 3
2).1 : 4
3).1 : 2
4).2 : 5