The plate current ip in a triode valve is given \[{{i}_{p}}=K{{({{V}_{p}}+\mu \,{{V}_{g}})}^{3/2}}\] where ip is in milliampere and Vp and Vg are in volt. If rp = 104 ohm, and \[{{g}_{m}}=5\times {{10}^{-3}}mho,\] then for \[{{i}_{p}}=8\,mA\] and \[{{V}_{p}}=300\,volt,\] what is the value of K and grid cut off voltage [Roorkee 1992]

• A.            ? 6V, (30)3/2                          
• B.            \[-\,6V,\,{{(1/30)}^{3/2}}\]
• C.            + 6V, (30)3/2                          
• D.            + 6V, (1/30)3/2