The work function (ϕ) of some metals is listed below. The number of metals which will show photoelectric effect when light of 300 nm wavelength falls on the metal is
Let Pbe a point in the first octant, whose image Qin the plane x+y=3(that is, the line segment PQis perpendicular to the plane x+y=3and the mid-point of PQlies in the plane x+y=3)lies on the z-axis. Let the distance of Pfrom the x-axis be 5. If Ris the image of Pin the xy-plane, then the length of PRis _______.
Let f:(0,∞)→R be a differentiable function such that f′(x)=2−xf(x) for all x∈(0,∞) and f(1)=1, then
Circle(s) touching x-axis at a distance 3 from the origin and having an intercept of length 27 on y-axis is (are)
Let m and n be two positive integers greater than 1.If α→0limαmecosαn−e=−(2e) then the value of nm is
Let a, b, cbe three non-zero real numbers such that the equation 3 acosx+2 bsinx=c, x∈[−2π,2π], has two distinct real roots αand βwith α+β=3π. Then, the value of abis _______.
Consider the cube in the first octant with sides OP,OQ and OR of length 1, along the x-axis, y-axis and z-axis, respectively, where O(0,0,0) is the origin. Let S(21,21,21) be the centre of the cube and T be the vertex of the cube opposite to the origin O such that S lies on the diagonal OT. If p=SP,q=SQ,r=SR and t=ST then the value of ∣(p×q)×(r×(t)∣is