Is the pixel value of a gray image also called it's intensity?

I found the pixel value of a gray image in MATLAB. Now what I'm confused about is this:

Can I call this pixel value, the intensity of this image?

The image and code I used attached. Please tell me if I'm making a blunder somewhere!!

IMAGE: https://drive.google.com/file/d/0Byy8GCAG9WQcRUtTb1hhNU51Q3M/edit

CODE:

clear all clc

img1=imread('C:\Users\Hamza\Desktop\780nm.jpg');

a=rgb2gray(img1);

c=impixel(a)

I1=c(1) % Intensity