Options (b) and (d) are correct about an electric motor.
An electric motor is a device which coverts electrical energy into mechanical energy.It works on the principle that when a current carrying coil is placed in a magnetic field, it experiences torque. Because of that torque, the coil rotates and thus the electrical energy gets converted into mechanical (motion) energy.
Answer:
2000 kg/m³
Explanation:
Density = (mass[kg])/(volume[m³])
Density of the brick = (.128kg)/(.02•.04•.08) = 2000 kg/m³
Answer:
Potential difference though which the electron was accelerated is 
Explanation:
Given :
De Broglie wavelength , 
Plank's constant , 
Charge of electron , 
Mass of electron , m=9.11\times 10^{-31}\ kg.
We know , according to de broglie equation :

Now , we know potential energy applied on electron will be equal to its kinetic energy .
Therefore ,

Putting all values in above equation we get ,

Hence , this is the required solution.
Answer:
The distance of car form the mirror is 330 cm.
Explanation:
height of object, h = 140 cm
height of image, h' = 14 cm
radius of curvature, R = 60 cm
focal length, f = R/2 = + 30 cm
Let the distance of image is v and the distance of object is u.

Use the formula of focal length

Answer:
1989.6Kg
Explanation:
The computation of the mass of the other body is given below:
As we know that
F = G × m1 × m2 ÷ r²
Here the G would have the constant value i.e. 6.67 × 10^-11Nm² / kg².
Now
6.5 × 10^-7N = 6.67 × 10^-11Nm² / kg² × 60Kg × m2 / (3.5m) ²
m2 = (F × r²) / (G × m1)
m2 = (6.5 × 10^-7N × (3.5m) ²) ÷ (6.67 × 10^-11Nm² / kg² × 60Kg)
= 1989.6Kg