Question

1. An electron moving with a velocity of 5×103m/s enters

into a uniform electric field and acquires a uniform

acceleration of 103m/s2

in the direction of initial velocity.

i. Find out the time in which electron velocity will be

doubled? 2

ii. How much distance electron would cover in this time?

2. Calculate the force of gravitation between two planets of

masses 3*1025 kg and 9*1025 kg if the distance between

the planets is 6000 km. take G = 6.67*10-11 Nm2

/Kg2

. 2

3. A car of mass 1000 kg moving at 40 m/sec strike to

another car of mass 1500 kg moving at 20 m/sec. after

collision the velo. of first car decreases to 30 m/sec.

calculate the final velo of second car. 2

4. In a cup of tea of 1400 ml sugar has a concentration of

12%, milk has a volume of 800 ml, concentration of water

is 20% and remaining is tea leaves. Calculate the volume

of sugar, water and tea leaves and the concentration of

milk and tea leaves. 2

5. Calculate the no of molecules in 170 g of NaNO3 and 600

g of MgSO4.​

Answer 1

Answer:

Initial velocity of the electron is u =5×10

4

m/s

Acceleration of the electron is a=10

4

m/s

2

From first equation of motion,

v=u+at

2u=u+at

t=u/a=(5×10

4

)/(10

4

)=5s

(C) 5

....

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