Don't get what is happening in matlab sin() function. need to know difference between sin(2*50*pi*t) and sin(2*1*pi*t)

Question

I am using Matlab to plot the sin graph. But when I put sin(250pi*t) it shows something else than the sinusoidal curve. Can you please help me to find out why it is happening? Thanks in advance.
Code:

t = 0:0.1:20;
x = sin(2*50*pi*t);
y = sin(2*1*pi*t);
subplot(2,1,1)
plot(t,x)
subplot(2,1,2)
plot(t,y)

This picture is showing the output of both sin waves