The electric powr consumed by a device may be calculate by using either of the two expression `P=I^2R` or `P=V^2/R`. The first expression indicates that it is directly proprotinal to R whereas the second expression indicates inverse proportiionality. How can the seemingly difference dependece of P on R in these expression be explained?

Carry out the multiplication of the expressions in each of the following pairs : 4p, q + r

Two point charges q_1 and q_2 are kept at a distance of r_(12) in air. Deduce the expression for the electrostatic potential energy of the system.

State the relationship between the power P, consumed by a device, its resistance R and current I, flowing through it An electric iron of resistance 20 ohm takes a current of 5A.Calculate the heat generated by it in 30 seconds.

If two positive integers p and q can be expression as p=ab^2 and q=a^3 ,a,b being prime numbers than LCM(p,q) is

Two cells, of e.m.f. 2E and E, and internal resistance 2 r and r respectivley are connected in parallel. Obtain the expression for the equivalent e.m.f and the internal resistance of the combination?

Derive the expression for the heat produced due to a current 'I' flowing for a time interval 't' through a resistor 'R' having a potential difference 'V' across its ends. With which name is this relation known ?

Draw a simple circuit of a CE transistor amplifier. Explain its working. Show that the voltage gain, A_V of the amplifier is given by A_v = - ( beta_(ac) R_L )/(r_i) where beta_(Ac) is the current gain, R_L is the load resistance and r_1 is the input resistance of the transistor. What is the significance of the negative sign in the expression for the voltage gain?

At constant volume and temperature conditions, the rates of diffusion r_(A) and r_(B) of gases A and B having densities P_(A) and P_(B) are related by the expression :

State the relationship between the power P, consumed by a device, its resistance R and current I, flowing through it An electric iron of resistance 20 ohm takes a current of 5A.Calculate its electric power?